A Section is the top-level grouping in the Harmonized Tariff Schedule, organizing related chapters by broad industry. There are 21 sections in the international Harmonized System, numbered with Roman numerals (I–XXI).
Examples include:
- Section I — Live animals; animal products (Chapters 1–5)
- Section XI — Textiles and textile articles (Chapters 50–63)
- Section XV — Base metals and articles of base metal (Chapters 72–83)
- Section XVI — Machinery and mechanical appliances; electrical equipment (Chapters 84–85)
- Section XVII — Vehicles, aircraft, vessels (Chapters 86–89)
Each section has Section Notes that are legally binding and frequently determine classification. Section notes commonly contain exclusions ("This section does not cover…") and definitions ("For the purposes of this Section…") — always check them before classifying a product within the section's chapters.