Customs & Tariff Glossary: 42 Terms Importers Need

Customs runs on its own vocabulary. Liquidation, Chapter 99, PSC, CAPE: each term is tied to a deadline, a duty rate or a refund you might be owed.

This glossary defines the 42 terms U.S. importers run into most often. Every definition is current as of October 2026, and most link to the statute, regulation or CBP page behind it.

Each entry opens with a one-sentence definition, then what it means in practice. Terms are grouped by where they show up: entry, classification, tariff programs, refunds and deadlines. If you'd rather see these terms applied to your own entries, a continuous duty analysis platform like Evana maps every entry by duty layer and flags what's refundable.

ACE (Automated Commercial Environment). ACE is CBP's electronic system for filing and processing imports and exports, and the single window where entries, entry summaries, refund claims and reports live. If you want your own liquidation dates, duty paid by line or refund status, ACE reports are the source (CBP).

Importer of record (IOR). The importer of record is the party legally responsible for an entry, including paying the duties and making sure the declared classification, value and origin are correct. It's also the party CBP refunds when money comes back (19 U.S.C. § 1484).

Customs broker (licensed). A licensed customs broker is a person or firm licensed by CBP to conduct customs business on behalf of importers, such as filing entries and classifying goods. The importer of record stays legally responsible for what a broker files (19 CFR Part 111).

Entry types (01, 11, 13). The entry type is a two-digit code on every entry that tells CBP which rules apply. Type 01 is a formal consumption entry, the standard for commercial shipments. Type 11 is an informal entry, generally for goods valued at $2,500 or less (19 CFR § 143.21). Type 13 is a new informal entry for international mail shipments that went live in ACE as a test on September 22, 2026 (GHY International).

CBP Form 7501 (entry summary). The entry summary, CBP Form 7501, is the document that declares each line's HTS code, value, origin and duty, and it's what your duty payment is calculated from. Every tariff layer you pay appears on it as its own line.

Customs bond (continuous or single). A customs bond is a surety contract that guarantees CBP will be paid the duties, taxes and penalties owed on your imports. A single transaction bond covers one entry; a continuous bond covers all entries for a year and is generally set at 10% of the duties, taxes and fees you paid in the prior 12 months, with a $50,000 minimum (CBP).

De minimis (Section 321). De minimis is the rule that once let shipments valued at $800 or less enter the U.S. duty-free with minimal paperwork. As of October 2026 it's suspended for all countries: an August 2025 executive order ended it worldwide, CBP wrote the suspension into its regulations on June 24, 2026, and a 2025 statute repeals it for commercial shipments effective July 1, 2027 (BDO; GHY International).

CSMS (Cargo Systems Messaging Service). CSMS is CBP's official broadcast channel for operational guidance to the trade, from new Chapter 99 codes to filing instructions. When a tariff changes overnight, filing details usually appear there first (CBP).

Duty. A duty is a tax on imported goods, collected by CBP and paid by the importer of record, not the foreign seller. Most U.S. duties are calculated as a percentage of the goods' customs value.

Ad valorem duty. An ad valorem duty is charged as a percentage of the goods' value, such as 5% of the transaction value. The alternative, a specific duty, is a fixed amount per unit; some HTS lines use both.

HTSUS (Harmonized Tariff Schedule of the United States). The HTSUS is the official U.S. list of product classifications and duty rates, maintained by the U.S. International Trade Commission. The first six digits follow the international Harmonized System; the U.S. adds digits up to 10, and the 8-digit level sets the duty rate (USITC).

Chapter 99. Chapter 99 is the part of the HTSUS that holds temporary and additional duties, such as Section 301, Section 232 and Section 338 tariffs. They appear on an entry as separate 9903 lines above your product's regular HTS line (USITC).

Binding ruling. A binding ruling is a written CBP decision on how a specific product should be classified, valued or marked, which CBP must follow for that transaction. You can request one before importing, and past rulings are searchable in CBP's CROSS database (19 CFR Part 177; CBP CROSS).

Country of origin. Country of origin is where a product was made, or last substantially transformed into a new article, not where it shipped from. It decides which Section 301, AD/CVD and trade-agreement rates apply, and most imports must be marked with it (19 U.S.C. § 1304).

Transaction value. Transaction value is the price actually paid or payable for goods sold for export to the U.S., plus certain additions like assists and royalties, and it's the default basis for customs value. International freight and insurance are generally excluded (19 U.S.C. § 1401a).

First sale. First sale is a valuation method that bases duty on the price in an earlier sale in a multi-tier chain, typically factory to middleman, instead of the price the U.S. importer paid. The earlier sale must be a bona fide, arm's-length sale for export to the U.S., with documents to prove it.

Tariff stack. A tariff stack is the full set of duties and fees charged on one import line: the base rate, any trade-remedy layers on top, then fees. See How to Calculate Import Duty for a worked example.

IEEPA tariffs. IEEPA tariffs were duties imposed in 2025 under the International Emergency Economic Powers Act, a 1977 sanctions law. The Supreme Court held in February 2026 that IEEPA doesn't authorize tariffs, and CBP is refunding them (50 U.S.C. § 1701).

Section 122. Section 122 of the Trade Act of 1974 lets the President impose a temporary import surcharge of up to 15% for up to 150 days to address balance-of-payments problems (19 U.S.C. § 2132). A 10% surcharge ran from February 24 to July 24, 2026; the Court of International Trade ruled against it in May, and the refund impact is still unsettled (Skadden).

Section 232. Section 232 of the Trade Expansion Act of 1962 lets the President impose duties on imports found to threaten national security (19 U.S.C. § 1862). Steel and aluminum articles are at 50%, charged on the full value of covered goods since an April 2026 proclamation (Congressional Research Service).

Section 301. Section 301 of the Trade Act of 1974 lets the U.S. Trade Representative impose duties in response to unfair foreign trade practices (19 U.S.C. § 2411). It covers the China lists in place since 2018 and, since July 24, 2026, country-level duties on roughly 60 trading partners, mostly at 10% or 12.5% (Z2Data).

Section 338. Section 338 of the Tariff Act of 1930 lets the President impose duties of up to 50%, and then an outright import ban, on countries found to discriminate against U.S. commerce (19 U.S.C. § 1338). Its first use came in 2026 against Canada, whose dairy, alcohol and motor vehicles have been barred from entry since September 29. More in our Canada coverage.

AD/CVD (antidumping and countervailing duties). AD/CVD are duties on specific products from specific countries, set to offset dumping below fair value (AD) or foreign government subsidies (CVD). The Commerce Department sets the rates, which can exceed every other layer combined (CBP).

FTA / USMCA. A free trade agreement (FTA) cuts or eliminates duties on goods that meet its rules of origin; USMCA is the agreement with Canada and Mexico. The preference isn't automatic: you claim it on the entry and must support it with origin documents (CBP).

Foreign-trade zone (FTZ). A foreign-trade zone is a designated area treated as outside U.S. customs territory for duty purposes, so goods can be stored, assembled or re-exported without paying duty until they enter U.S. commerce (19 U.S.C. § 81c).

MPF (Merchandise Processing Fee). The Merchandise Processing Fee is a CBP user fee of 0.3464% of the value of formally entered goods, with a per-entry minimum and maximum adjusted each October (GHY International).

HMF (Harbor Maintenance Fee). The Harbor Maintenance Fee is a 0.125% charge on the value of cargo unloaded at U.S. ports, so it applies to ocean shipments but not air (26 U.S.C. § 4461).

CAPE. CAPE (Consolidated Administration and Processing of Entries) is the ACE tool CBP built to process IEEPA duty refunds. It opened April 20, 2026, and Phase 3, for certain finally liquidated entries, opened October 6. As of September 11, 2026, CBP had accepted $134.7 billion in claims and sent $122 billion to Treasury (CBP). Start with our CAPE Phase 3 guide.

ACH refund. An ACH refund is a CBP refund paid by electronic bank transfer to an account the importer has enrolled in ACE. CBP holds IEEPA refunds until valid ACH details are on file; as of September 11, 2026, 20,184 refunds worth $1.3 billion were stuck for that reason (Troutman Pepper Locke; IEEPA Refunds by the Numbers).

Duty drawback. Duty drawback is a refund of up to 99% of the duties, taxes and fees paid on imported goods that are later exported or destroyed. Claims are due within five years of import and filed in ACE (19 U.S.C. § 1313). IEEPA duties come back through CAPE, not drawback. Full guide: Duty Drawback, Explained.

Drawback types. The four main drawback types are manufacturing, unused merchandise, rejected merchandise and substitution. Substitution lets you claim on exported goods that are interchangeable with what you imported; for unused merchandise, that means the same 8-digit HTS subheading (19 CFR Part 190).

Accelerated payment. Accelerated payment is a drawback privilege that lets CBP pay a claim before it liquidates, backed by a bond. Without it, you wait for the claim to liquidate, which can take years; with it, payment generally comes within weeks (CBP).

PSC (Post Summary Correction). A Post Summary Correction is an electronic fix to an entry summary filed in ACE before liquidation. It must be filed within 300 days of entry and at least 15 days before the scheduled liquidation date, and it's the cheapest way to correct a classification or value error (International Trade Insights).

Protest. A protest is a formal challenge to a CBP decision, such as a liquidation, rate or classification, filed within 180 days after liquidation. If CBP denies it, the next step is the Court of International Trade (19 U.S.C. § 1514).

Reconciliation. Reconciliation is a CBP program that lets you flag entries when some information, such as final value, isn't known at filing, then report it later in a single reconciliation entry. The reconciliation entry is generally due within 21 months of the earliest flagged entry summary (CBP).

Reliquidation. Reliquidation is a second liquidation that changes an entry's final duty, either by CBP within 90 days of the original or by court order (19 U.S.C. § 1501). It's how many IEEPA refunds on older entries are being paid.

Prior disclosure. A prior disclosure is a voluntary report to CBP of a customs violation before CBP opens an investigation into it. Doing so, and paying the duties owed, sharply reduces the potential penalty (19 U.S.C. § 1592).

Liquidation. Liquidation is CBP's final computation of the duties, taxes and fees owed on an entry. It typically happens about 314 days after entry; an entry not liquidated within one year is "deemed liquidated" as declared, unless CBP extends it, up to four years (19 U.S.C. § 1504). See Liquidation, Explained.

Finally liquidated. An entry is finally liquidated once the 180-day protest window has closed with no protest, or once any protest has been fully resolved. Finally liquidated entries generally can't be reopened without a court order or a special program, which is why CAPE Phase 3 was built separately for them (CBP).

Learning Resources ruling. Learning Resources, Inc. v. Trump is the Supreme Court decision of February 20, 2026 holding that IEEPA does not authorize the President to impose tariffs. It's a statutory ruling, not a constitutional one, and it's the reason CBP is refunding roughly $166 billion in IEEPA duties across 53 million entry summaries (Faegre Drinker).

Court of International Trade (CIT). The U.S. Court of International Trade is the federal court in New York that hears disputes over customs duties, tariffs and trade laws. Denied protests and tariff challenges, including the Section 122 case, go there.

Recordkeeping requirement. Importers must keep entry records, including invoices, contracts and proof of payment, for five years from the date of entry. Missing records can turn a simple CBP question into a penalty (19 CFR § 163.4).

This vocabulary used to be the broker's problem. In 2026 it became the CFO's, because the difference between "liquidated" and "finally liquidated," or drawback and CAPE, now decides whether money comes back. Learn the five deadline terms first (PSC, liquidation, protest, drawback's five years, finally liquidated); they're the ones that close doors.

Related on Trade Talk: Tariff Authorities, Explained · Liquidation, Explained · Tariff & Duty FAQ

Got questions? Drop a comment below. Ask our licensed customs brokers, and they'll get right back to you here in the comments.