Justice THOMASdelivered the opinion of the Court.
In an effort to improve the collection of sales and use taxes for items purchased online, the State of Colorado passed a law requiring retailers that do not collect Colorado sales or use tax to notify Colorado customers of their use-tax liability and to report tax-related information to customers and the Colorado Department of Revenue. We must decide whether the Tax Injunction Act, which provides that federal district courts "shall not enjoin, suspend or restrain the assessment, levy or collection of any tax under State law," 28 U.S.C. § 1341, bars a suit to enjoin the enforcement of this law. We hold that it does not.
I
A
Like many States, Colorado has a complementary sales-and-use tax regime. Colorado imposes both a 2.9 percent tax on the sale of tangible personal property within the State, Colo.Rev.Stat. §§ 39-26-104(1)(a), 39-26-106(1)(a)(II) (2014), and an equivalent use tax for any property stored, used, or consumed in Colorado on which a sales tax was not paid to a retailer, §§ 39-26-202(1)(b), 39-26-204(1). Retailers with a physical presence in Colorado must collect the sales or use tax from consumers at the point of sale and remit the proceeds to the Colorado Department of Revenue (Department). §§ 39-26-105(1), 39-26-106(2)(a). But under our negative Commerce Clause precedents, Colorado may not require retailers who lack a physical presence in the State to collect these taxes on behalf of the Department. See Quill Corp. v. North Dakota,504 U.S. 298, 315-318, 112 S.Ct. 1904, 119 L.Ed.2d 91 (1992). Thus, Colorado requires its consumers who purchase tangible personal property from a retailer that does not collect these taxes (a "noncollecting retailer") to fill out a return and remit the taxes to the Department directly. § 39-26-204(1).
Voluntary compliance with the latter requirement is relatively low, leading to a significant loss of tax revenue, especially as Internet retailers have increasingly displaced their brick-and-mortar kin. In the decade before this suit was filed in 2010, e-commerce more than tripled. App. 28. With approximately 25 percent of taxes unpaid on Internet sales, Colorado estimated in 2010 that its revenue loss attributable *1128to noncompliance would grow by more than $20 million each year. App. 30-31.
In hopes of stopping this trend, Colorado enacted legislation in 2010 imposing notice and reporting obligations on noncollecting retailers whose gross sales in Colorado exceed $100,000. Three provisions of that Act, along with their implementing regulations, are at issue here.
First, noncollecting retailers must "notify Colorado purchasers that sales or use tax is due on certain purchases ... and that the state of Colorado requires the purchaser to file a sales or use tax return."§ 39-21-112(3.5)(c)(I); see also 1 Colo.Code Regs. § 201-1:39-21-112.3.5(2) (2014), online at http://www.sos.co.us/CRR (as visited Feb. 27, 2015, and available in the Clerk of Court's case file). The retailer must provide this notice during each transaction with a Colorado purchaser, ibid.,and is subject to a penalty of $5 for each transaction in which it fails to do so, Colo.Rev.Stat. § 39-21-112(3.5)(c)(II).
Second, by January 31 of each year, each noncollecting retailer must send a report to all Colorado purchasers who bought more than $500 worth of goods from the retailer in the previous year. § 39-21-112(3.5)(d)(I); 1 Colo.Code Regs. §§ 201-1:39-21-112.3.5(3)(a), (c). That report must list the dates, categories, and amounts of those purchases. Colo.Rev.Stat. § 39-21-112(3.5)(d)(I); see also 1 Colo.Code Regs. §§ 201-1:39-21-112.3.5(3)(a), (c). It must also contain a notice stating that Colorado "requires a sales or use tax return to be filed and sales or use tax paid on certain Colorado purchases made by the purchaser from the retailer." Colo.Rev.Stat. § 39-21-112(3.5)(d)(I)(A). The retailer is subject to a penalty of $10 for each report it fails to send. § 39-21-112(3.5)(d)(III)(A); see also 1 Colo.Code Regs. § 201-1:39-21-112.3.5(3)(d).
Finally, by March 1 of each year, noncollecting retailers must send a statement to the Department listing the names of their Colorado customers, their known addresses, and the total amount each Colorado customer paid for Colorado purchases in the prior calendar year. Colo.Rev.Stat. § 39-21-112(3.5)(d)(II)(A); 1 Colo.Code Regs. § 201-1:39-21-112.3.5(4). A noncollecting retailer that fails to make this report is subject to a penalty of $10 for each customer that it should have listed in the report. Colo.Rev.Stat. § 39-21-112(3.5)(d)(III)(B); see also 1 Colo.Code Regs. § 201-1:39-21-112.3.5(4)(f).
B
Petitioner Direct Marketing Association is a trade association of businesses and organizations that market products directly to consumers, including those in Colorado, via catalogs, print advertisements, broadcast media, and the Internet. Many of its members have no physical presence in Colorado and choose not to collect Colorado sales and use taxes on Colorado purchases. As a result, they are subject to Colorado's notice and reporting requirements.
In 2010, Direct Marketing Association brought suit in the United States District Court for the District of Colorado against the Executive Director of the Department, alleging that the notice and reporting requirements violate provisions of the United States and Colorado Constitutions. As relevant here, Direct Marketing Association alleged that the provisions (1) discriminate against interstate commerce and (2) impose undue burdens on interstate commerce, all in violation of this Court's negative Commerce Clause precedents. At the request of both parties, the District Court stayed all challenges except these two, in *1129order to facilitate expedited consideration. It then granted partial summary judgment to Direct Marketing Association and permanently enjoined enforcement of the notice and reporting requirements. App. to Pet. for Cert. B-1 to B-25.
Exercising appellate jurisdiction under 28 U.S.C. § 1292(a)(1), the United States Court of Appeals for the Tenth Circuit reversed. Without reaching the merits, the Court of Appeals held that the District Court lacked jurisdiction over the suit because of the Tax Injunction Act (TIA), 28 U.S.C. § 1341. Acknowledging that the suit "differs from the prototypical TIA case," the Court of Appeals nevertheless found it barred by the TIA because, if successful, it "would limit, restrict, or hold back the state's chosen method of enforcing its tax laws and generating revenue." 735 F.3d 904, 913 (2013).
We granted certiorari, 573 U.S. ----, 134 S.Ct. 2901, 189 L.Ed.2d 855 (2014), and now reverse.
II
Enacted in 1937, the TIA provides that federal district courts "shall not enjoin, suspend or restrain the assessment, levy or collection of any tax under State law where a plain, speedy and efficient remedy may be had in the courts of such State." § 1341. The question before us is whether the relief sought here would "enjoin, suspend or restrain the assessment, levy or collection of any tax under State law." Because we conclude that it would not, we need not consider whether "a plain, speedy and efficient remedy may be had in the courts of" Colorado.
The District Court enjoined state officials from enforcing the notice and reporting requirements. Because an injunction is clearly a form of equitable relief barred by the TIA, the question becomes whether the enforcement of the notice and reporting requirements is an act of "assessment, levy or collection." We need not comprehensively define these terms to conclude that they do not encompass enforcement of the notice and reporting requirements at issue.
In defining the terms of the TIA, we have looked to federal tax law as a guide. See, e.g.,Hibbs v. Winn,542 U.S. 88, 100, 124 S.Ct. 2276, 159 L.Ed.2d 172 (2004). Although the TIA does not concern federal taxes, it was modeled on the Anti-Injunction Act (AIA), which does. See Jefferson County v. Acker,527 U.S. 423, 434-435, 119 S.Ct. 2069, 144 L.Ed.2d 408 (1999). The AIA provides in relevant part that "no suit for the purpose of restraining the assessment or collection of any tax shall be maintained in any court by any person." 26 U.S.C. § 7421(a). We assume that words used in both Acts are generally used in the same way, and we discern the meaning of the terms in the AIA by reference to the broader Tax Code. Hibbs, supra,at 102-105, 124 S.Ct. 2276; id.,at 115, 124 S.Ct. 2276(KENNEDY, J., dissenting). Read in light of the Federal Tax Code at the time the TIA was enacted (as well as today), these three terms refer to discrete phases of the taxation process that do not include informational notices or private reports of information relevant to tax liability.
To begin, the Federal Tax Code has long treated information gathering as a phase of tax administration procedure that occurs before assessment, levy, or collection. See §§ 6001-6117; §§ 1500-1524 (1934 ed.); see also § 1533 ("All provisions of law for the ascertainment of liability to any tax, or the assessment or collection thereof, shall be held to apply ..."). This step includes private reporting of information used to determine tax liability, see, e.g., *1130§ 1511(a), including reports by third parties who do not owe the tax, see, e.g.,§ 6041 et seq. (2012 ed.); see also §§ 1512(a)-(b) (1934 ed.) (authorizing a collector or the Commissioner of Internal Revenue, when a taxpayer fails to file a return, to make a return "from his own knowledge and from such information as he can obtain through testimony or otherwise").
"Assessment" is the next step in the process, and it refers to the official recording of a taxpayer's liability, which occurs after information relevant to the calculation of that liability is reported to the taxing authority. See § 1530. In Hibbs,the Court noted that "assessment," as used in the Internal Revenue Code, "involves a 'recording' of the amount the taxpayer owes the Government." 542 U.S., at 100, 124 S.Ct. 2276(quoting § 6203 (2000 ed.)). It might also be understood more broadly to encompass the process by which that amount is calculated. See United States v. Galletti,541 U.S. 114, 122, 124 S.Ct. 1548, 158 L.Ed.2d 279 (2004); see also Hibbs, supra,at 100, n. 3, 124 S.Ct. 2276. But even understood more broadly, "assessment" has long been treated in the Tax Code as an official action taken based on information already reported to the taxing authority. For example, not many years before it passed the TIA, Congress passed a law providing that the filing of a return would start the running of the clock for a timely assessment. See, e.g., Revenue Act of 1924, Pub.L. 68-176, § 277(a), 43 Stat. 299. Thus, assessment was understood as a step in the taxation process that occurred after, and was distinct from, the step of reporting information pertaining to tax liability.
"Levy," at least as it is defined in the Federal Tax Code, refers to a specific mode of collection under which the Secretary of the Treasury distrains and seizes a recalcitrant taxpayer's property. See 26 U.S.C. § 6331 (2012 ed.); § 1582 (1934 ed.). Because the word "levy" does not appear in the AIA, however, one could argue that its meaning in the TIA is not tied to the meaning of the term as used in federal tax law. If that were the case, one might look to contemporaneous dictionaries, which defined "levy" as the legislative function of laying or imposing a tax and the executive functions of assessing, recording, and collecting the amount a taxpayer owes. See Black's Law Dictionary 1093 (3d ed. 1933) (Black's); see also Webster's New International Dictionary 1423 (2d ed. 1939) ("To raise or collect, as by assessment, execution, or other legal process, etc.; to exact or impose by authority ..."); §§ 1540, 1544 (using "levying" and "levied" in the more general sense of an executive imposition of a tax liability). But under any of these definitions, "levy" would be limited to an official governmental action imposing, determining the amount of, or securing payment on a tax.
Finally, "collection" is the act of obtaining payment of taxes due. See Black's 349 (defining "collect" as "to obtain payment or liquidation" of a debt or claim). It might be understood narrowly as a step in the taxation process that occurs after a formal assessment. Consistent with this understanding, we have previously described it as part of the "enforcement process ... that 'assessment' sets in motion." Hibbs, supra,at 102, n. 4, 124 S.Ct. 2276. The Federal Tax Code at the time the TIA was enacted provided for the Commissioner of Internal Revenue to certify a list of assessments "to the proper collectors ... who [would] proceed to collect and account for the taxes and penalties so certified." § 1531. That collection process began with the collector "giv[ing] notice to each person liable to pay any taxes stated [in the list] ... stating the amount of such taxes and demanding payment thereof."
*1131§ 1545(a). When a person failed to pay, the Government had various means to collect the amount due, including liens, § 1560, distraint, § 1580, forfeiture, and other legal proceedings, § 1640. Today's Tax Code continues to authorize collection of taxes by these methods. § 6302 (2012 ed.). "Collection" might also be understood more broadly to encompass the receipt of a tax payment before a formal assessment occurs. For example, at the time the TIA was enacted, the Tax Code provided for the assessment of money already received by a person "required to collector withhold any internal-revenue tax from any other person," suggesting that at least some act of collection might occur before a formal assessment. § 1551 (1934 ed.) (emphasis added). Either way, "collection" is a separate step in the taxation process from assessment and the reporting on which assessment is based.
So defined, these terms do not encompass Colorado's enforcement of its notice and reporting requirements. The Executive Director does not seriously contend that the provisions at issue here involve a "levy"; instead she portrays them as part of the process of assessment and collection. But the notice and reporting requirements precede the steps of "assessment" and "collection." The notice given to Colorado consumers, for example, informs them of their use-tax liability and prompts them to keep a record of taxable purchases that they will report to the State at some future point. The annual summary that the retailers send to consumers provides them with a reminder of that use-tax liability and the information they need to fill out their annual returns. And the report the retailers file with the Department facilitates audits to determine tax deficiencies. After each of these notices or reports is filed, the State still needs to take further action to assess the taxpayer's use-tax liability and to collect payment from him. See Colo.Rev.Stat. § 39-26-204(3)(describing the procedure for "assessing and collecting [use] taxes" on the basis of returns filed by consumers and collecting retailers). Colorado law provides for specific assessment and collection procedures that are triggered after the State has received the returns and made the deficiency determinations that the notice and reporting requirements are meant to facilitate. See § 39-26-210; 1 Colo.Code Regs. § 201-1:39-21-107(1) ("The statute of limitations on assessments of ... sales [and] use ... tax ... shall be three years from the date the return was filed ...").
Enforcement of the notice and reporting requirements may improve Colorado's ability to assess and ultimately collect its sales and use taxes from consumers, but the TIA is not keyed to all activities that may improve a State's ability to assess and collect taxes. Such a rule would be inconsistent not only with the text of the statute, but also with our rule favoring clear boundaries in the interpretation of jurisdictional statutes. See Hertz Corp. v. Friend,559 U.S. 77, 94, 130 S.Ct. 1181, 175 L.Ed.2d 1029 (2010). The TIA is keyed to the acts of assessment, levy, and collection themselves, and enforcement of the notice and reporting requirements is none of these.1
*1132B
Apparently concluding that enforcement of the notice and reporting requirements was not itself an act of "assessment, levy or collection," the Court of Appeals did not rely on those terms to hold that the TIA barred the suit. Instead, it adopted a broad definition of the word "restrain" in the TIA, which bars not only suits to "enjoin ... assessment, levy or collection" of a state tax but also suits to "suspend or restrain" those activities. Specifically, the Court of Appeals concluded that the TIA bars any suit that would "limit, restrict, or hold back" the assessment, levy, or collection of state taxes. 735 F.3d, at 913. Because the notice and reporting requirements are intended to facilitate collection of taxes, the Court of Appeals reasoned that the relief Direct Marketing Association sought and received would "limit, restrict, or hold back" the Department's collection efforts. That was error.
"Restrain," standing alone, can have several meanings. One is the broad meaning given by the Court of Appeals, which captures orders that merely inhibitacts of "assessment, levy and collection." See Black's 1548. Another, narrower meaning, however, is "[t]o prohibit from action; to put compulsion upon ... to enjoin," ibid.,which captures only those orders that stop (or perhaps compel) acts of "assessment, levy and collection."
To resolve this ambiguity, we look to the context in which the word is used. Robinson v. Shell Oil Co.,519 U.S. 337, 341, 117 S.Ct. 843, 136 L.Ed.2d 808 (1997). The statutory context provides several clues that lead us to conclude that the TIA uses the word "restrain" in its narrower sense. Looking to the company "restrain" keeps, Jarecki v. G.D. Searle & Co.,367 U.S. 303, 307, 81 S.Ct. 1579, 6 L.Ed.2d 859 (1961), we first note that the words "enjoin" and "suspend" are terms of art in equity, see Fair Assessment in Real Estate Assn., Inc. v. McNary,454 U.S. 100, 126, and n. 13, 102 S.Ct. 177, 70 L.Ed.2d 271 (1981)(Brennan, J., concurring). They refer to different equitable remedies that restrict or stop official action to varying degrees, strongly suggesting that "restrain" does the same. See Hibbs,542 U.S., at 118, 124 S.Ct. 2276(KENNEDY, J., dissenting); see also Jefferson County,527 U.S., at 433, 119 S.Ct. 2069.
Additionally, as used in the TIA, "restrain" acts on a carefully selected list of technical terms-"assessment, levy, collection"-not on an all-encompassing term, like "taxation." To give "restrain" the broad meaning selected by the Court of Appeals would be to defeat the precision of that list, as virtually any court action related to any phase of taxation might be said to "hold back" "collection." Such a broad construction would thus render "assessment [and] levy"-not to mention "enjoin [and] suspend"-mere surplusage, a result we try to avoid. See Hibbs, supra,at 101, 124 S.Ct. 2276(interpreting the terms of the TIA to avoid superfluity).
Assigning the word "restrain" its meaning in equity is also consistent with our recognition that the TIA "has its roots in equity practice." Tully v. Griffin, Inc.,429 U.S. 68, 73, 97 S.Ct. 219, 50 L.Ed.2d 227 (1976). Under the comity doctrine that the TIA partially codifies, *1133Levin v. Commerce Energy, Inc.,560 U.S. 413, 431-432, 130 S.Ct. 2323, 176 L.Ed.2d 1131 (2010), courts of equity exercised their "sound discretion" to withhold certain forms of extraordinary relief, Great Lakes Dredge & Dock Co. v. Huffman,319 U.S. 293, 297, 63 S.Ct. 1070, 87 L.Ed. 1407 (1943); see also Dows v. Chicago,11 Wall. 108, 110, 20 L.Ed. 65 (1871). Even while refusing to grant certain forms of equitable relief, those courts did not refuse to hear every suit that would have a negative impact on States' revenues. See, e.g., Henrietta Mills v. Rutherford County,281 U.S. 121, 127, 50 S.Ct. 270, 74 L.Ed. 737 (1930); see also 5 R. Paul & J. Mertens, Law of Federal Income Taxation § 42.139 (1934)(discussing the word "restraining" in the AIA in its equitable sense). The Court of Appeals' definition of "restrain," however, leads the TIA to bar every suit with such a negative impact. This history thus further supports the conclusion that Congress used "restrain" in its narrower, equitable sense, rather than in the broad sense chosen by the Court of Appeals.
Finally, adopting a narrower definition is consistent with the rule that "[j]urisdictional rules should be clear."Grable & Sons Metal Products, Inc. v. Darue Engineering & Mfg.,545 U.S. 308, 321, 125 S.Ct. 2363, 162 L.Ed.2d 257 (2005)(THOMAS, J., concurring); see also Hertz Corp., supra,at 94, 130 S.Ct. 1181. The question-at least for negative injunctions-is whether the relief to some degree stops "assessment, levy or collection," not whether it merely inhibits them. The Court of Appeals' definition of "restrain," by contrast, produces a " 'vague and obscure' " boundary that would result in both needless litigation and uncalled-for dismissal, Sisson v. Ruby,497 U.S. 358, 375, 110 S.Ct. 2892, 111 L.Ed.2d 292 (1990)(SCALIA, J., concurring in judgment), all in the name of a jurisdictional statute meant to protect state resources.
Applying the correct definition, a suit cannot be understood to "restrain" the "assessment, levy or collection" of a state tax if it merely inhibits those activities.2
III
We take no position on whether a suit such as this one might nevertheless be barred under the "comity doctrine," which "counsels lower federal courts to resist engagement in certain cases falling within their jurisdiction."
*1134Levin, supra,at 421, 130 S.Ct. 2323. Under this doctrine, federal courts refrain from "interfer[ing] ... with the fiscal operations of the state governments ... in all cases where the Federal rights of the persons could otherwise be preserved unimpaired." Id.,at 422, 130 S.Ct. 2323(internal quotation marks omitted).
Unlike the TIA, the comity doctrine is nonjurisdictional. And here, Colorado did not seek comity from either of the courts below. Moreover, we do not understand the Court of Appeals' footnote concerning comity to be a holding that comity compels dismissal. See 735 F.3d, at 920, n. 11("Although we remand to dismiss [petitioner's] claims pursuant to the TIA, we note that the doctrine of comity also militates in favor of dismissal"). Accordingly, we leave it to the Tenth Circuit to decide on remand whether the comity argument remains available to Colorado.
* * *
Because the TIA does not bar petitioner's suit, we reverse the judgment of the Court of Appeals. Like the Court of Appeals, we express no view on the merits of those claims and remand the case for further proceedings consistent with this opinion.
It is so ordered.