Definition
A tax, duty, or toll levied on goods brought into a country; a customs duty on imported merchandise. In its narrower and most precise legal sense, an impost is a charge imposed at the point of importation — the fiscal mechanism by which a sovereign taxes the movement of foreign goods across its borders. In a broader sense, the term extends to any tax, duty, or imposition not otherwise captured by the more specific designations of "taxes" and "excises," functioning as a residual category in the taxonomy of public revenue.
Two usages persist in legal sources:
1. Narrow: A customs duty or tariff specifically applicable to imported goods and merchandise.
2. Broad: Any governmental levy, tax, or compulsory contribution; a general term of fiscal imposition synonymous in some contexts with duty, toll, or tribute.
Common Language
Modern common usage (Wiktionary): A tax, tariff, or duty that is imposed, especially on merchandise. Secondarily, in horse racing, the weight a horse must carry as a handicap.
Historical common usage (Webster's 1913): That which is imposed or levied; a tax, tribute, or duty; especially, a duty or tax laid by government on goods imported into a country. Webster's also records an architectural sense: the top member of a pillar, pier, or wall upon which the weight of an arch rests.
The gap between common and legal meaning is modest but worth flagging. In ordinary usage, "impost" can refer loosely to any tax or burden, and the architectural sense (the load-bearing capstone of an arch) is entirely unrelated to fiscal law. In constitutional and customs law, impost carries a narrower, more technical weight — it is the term used in the Import-Export Clause and in the foundational customs jurisprudence of the early republic. A researcher encountering "impost" in a general text must determine from context whether the writer means the precise customs duty or the broader fiscal sense.
Common Confusion
IMPOST vs. DUTY vs. TAX vs. EXCISE: These terms overlap substantially in historical sources and are sometimes used interchangeably. The constitutional significance lies in their differences. In American constitutional usage, the Taxing Clause grants Congress power to lay and collect "taxes, duties, imposts, and excises" — a formulation that treats impost as a distinct category, not a synonym for the others. Courts and commentators, including Story and Marshall, used impost to mean specifically a duty on imports, reserving excise for taxes on domestic goods, production, or transactions. Researchers should resist collapsing these terms in constitutional contexts while acknowledging that in non-constitutional legal writing, impost frequently appears as a general synonym for any fiscal levy.
Why It Matters in Research
The term's importance in American legal history is disproportionate to its modern frequency. Impost appears directly in the constitutional text — Article I, Section 8 grants Congress the power to lay and collect taxes, duties, imposts, and excises — making it a term of art with constitutional dimension. Chief Justice Marshall's usage in Gibbons v. Ogden (11 Wheaton 1, 1824) and related commerce and customs cases shaped early doctrine on the scope of federal import power. Story's Commentaries on the Constitution treated impost as the operative concept for customs revenue, distinct from internal excises.
For corpus researchers, the key navigational challenges are:
1. Period variation: Pre-constitutional and early republic sources use impost broadly, as a near-synonym for any tax. Post-constitutional sources in the American context increasingly narrow the term to import duties specifically. The same word can mean different things depending on whether the source predates or postdates 1787.
2. British vs. American usage: English legal sources (and English-origin dictionaries like Burrill) carry the French and Latin roots forward in both broad and narrow senses. American legal usage pulled the term toward its constitutional meaning. A treatise written in England in 1790 may use impost in ways that do not translate cleanly into American constitutional categories.
3. The residual category problem: Anderson's entry notes that impost "comprehends every species of tax or contribution not included under the ordinary terms 'taxes and excises.'" This residual function makes impost a useful analytical backstop in historical texts but a tricky target for keyword searches — a passage using impost may be about import duties, or may be filling a taxonomic gap with a catch-all term.
4. Corpus connections: Impost connects directly to the commerce power literature, to customs and tariff statutes, and to the Import-Export Clause (Article I, Section 10), which restricts state power to lay "imposts or duties on imports or exports." Researchers working on federal-state revenue conflicts in the nineteenth century will find impost appearing at the intersection of all these doctrinal threads.
Historical Dictionary Support
Anderson and Burrill are in substantial agreement. Both define impost primarily as a customs duty on imported goods and acknowledge a broader sense encompassing any tax or levy. Burrill grounds his narrow definition in Marshall (11 Wheaton) and Story's Commentaries, giving the entry direct constitutional pedigree. Anderson notes the synonymy with duty and the residual function — comprehending taxes not otherwise named — which reflects the constitutional drafting context.
Neither dictionary fully develops the constitutional tension between the narrow and broad senses, though both flag it implicitly. What historical dictionaries do not adequately address is the Import-Export Clause's use of the term as a restriction on state power, not just a grant of federal power — a distinction that matters significantly in sovereignty and federalism research. Researchers should not rely on dictionary definitions alone when working through the constitutional case law; the doctrinal evolution in the courts moved faster than the dictionaries tracked.
Webster's 1913 confirms the general English usage and adds the architectural sense, which is irrelevant to legal research but useful for disambiguation when the term appears in non-legal historical texts.
Jurisdictional Note
In American law, impost is primarily a federal constitutional term. State governments are broadly restricted from laying imposts on imports or exports without congressional consent under Article I, Section 10. In international trade and tariff law, the term has been largely displaced in modern usage by tariff, duty, and customs, but retains force in constitutional argument and historical analysis.