Definition
Imposts are taxes, duties, or impositions levied by a government on goods or persons. In constitutional and fiscal law, the term carries two related but distinct senses:
1. Duties on imported goods or merchandise. In this sense, imposts are taxes collected at the point of entry on foreign goods brought into a sovereign's territory. This is the dominant legal meaning and the one most relevant to constitutional research.
2. Taxes, duties, or impositions generally. In broader usage — particularly in older authorities and constitutional texts — "imposts" functions as a near-synonym for any government exaction, sometimes encompassing internal revenue charges alongside import duties.
The U.S. Constitution uses the term in both registers: Article I, Section 8 grants Congress power "to lay and collect Taxes, Duties, Imposts and Excises," while Article I, Section 10 prohibits states from laying "any Imposts or Duties on Imports or Exports" without congressional consent. In constitutional interpretation, the Article I, Section 8 usage is broad; the Section 10 usage is narrower and specifically tied to foreign commerce.
Common Language
Modern common usage (Wiktionary): Plural of impost — no independent definition offered beyond the base word, reflecting that "imposts" rarely appears in modern ordinary English outside legal and historical contexts.
Historical common usage (Webster's 1913): A tax; a toll; a tribute; especially, a duty or tax laid by government on imported goods and merchandise.
The ordinary meaning tracks the legal meaning closely, which might suggest the COMMON LANGUAGE section can be omitted — but the gap worth flagging is one of register and precision. In common historical usage, "impost" was a loose synonym for any government tax. In constitutional law, the word carries a specific allocation of power between Congress and the states, and conflating it with general taxation or with "excises" can mislead research into the Taxing and Spending Clause, the Import-Export Clause, and the Uniformity Clause.
Common Confusion
Imposts vs. Duties: The terms are frequently used interchangeably in both legal and lay sources, but historical authorities drew a distinction. Duties were sometimes understood to include charges on exports as well as imports, while imposts were more specifically confined to inbound foreign goods. Cowel's definition preserved in Black's makes a further distinction between imposts (charged on incoming merchandise) and customs (profit taken on goods shipped out), though both Black's editions acknowledge the terms are "frequently confounded." For constitutional purposes, the distinction matters most in Import-Export Clause analysis.
Imposts vs. Excises: The constitutional enumeration — "Taxes, Duties, Imposts and Excises" — is not redundant. Excises are internal taxes on the manufacture, sale, or consumption of domestic goods and services. Imposts are levied at the border on foreign goods. Conflating the two obscures the different uniformity requirements that attach to each under Article I.
Why It Matters in Research
Constitutional corpus navigation: "Imposts" is a term of constitutional art. Its appearances in the Federalist Papers, the ratification debates (especially Elliott's Debates), and Story's Commentaries on the Constitution are the primary interpretive sources. Researchers tracing the original understanding of the Taxing Clause or the Import-Export Clause should begin with those texts rather than later case law, which tends to use "tariff," "duty," and "customs" in preference to "impost."
Shift in working vocabulary: By the mid-nineteenth century, "impost" as an operative term in American statutory and judicial language was largely displaced by "duty," "tariff," and "customs." This means a researcher searching Law Mind sources chronologically will find "imposts" concentrated in founding-era and early republic materials, then declining sharply. Absence of the term in later sources does not mean the concept is absent — it means the vocabulary changed.
Import-Export Clause trap: The Article I, Section 10 prohibition on state imposts is a recurring issue in dormant Commerce Clause and federalism research. Cases addressing state inspection fees, port charges, and import regulations often turn on whether a state exaction qualifies as an "impost or duty on imports or exports." Researchers should not assume that modern cases use "impost" — they typically frame the issue in Commerce Clause or Supremacy Clause terms, but the underlying constitutional hook is the Import-Export Clause.
Plural form in sources: Law Mind historical sources nearly always use the plural "imposts" rather than the singular. Searching the singular alone may miss relevant passages.
Historical Dictionary Support
All three shelf sources — Black's (1st), Black's (2nd), and Bouvier's — converge on the same core definition: taxes, duties, or impositions, with the dominant sense being a duty on imported goods or merchandise. All three cite Story's Commentaries § 949 as authority, making that passage the canonical historical reference point.
Black's (1st and 2nd) preserves Cowel's distinction between imposts and customs, which is historically useful even though both editions acknowledge the terms are "frequently confounded." This is a rare instance of the historical dictionaries flagging their own definitional instability — worth noting when advising researchers.
Bouvier's adds the constitutional dimension most explicitly, quoting the relevant clauses and citing the Federalist No. 30, Elliott's Debates, and Cooley on Taxation alongside Story. Bouvier's is therefore the most useful of the three for researchers approaching the term from a constitutional or fiscal federalism angle.
What the historical sources miss: None of the three dictionary entries address the later displacement of "impost" by "duty" and "tariff" in working legal vocabulary, nor do they explain the interpretive significance of the term's placement in both the Taxing Clause and the Import-Export Clause. Researchers relying solely on these definitions may underestimate how constitutionally freighted the term became in nineteenth-century Commerce Clause litigation.
Jurisdictional Note
The term "imposts" as a matter of operative law is almost exclusively federal in American legal research — the Constitution reserves the power to lay imposts to Congress and largely strips it from the states. State-level research involving taxes on imported goods will typically frame issues under the Import-Export Clause, the dormant Commerce Clause, or state administrative law, without using the word "impost" at all.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Taxing and Spending Clause; Import-Export Clause; Customs and Duties.