Trade in goods is both a category of trade and, typically, a chapter heading in a trade agreement, covering tangible products that cross a border as distinguished from trade in services. Each agreement’s own text sets what its goods chapter covers and what falls to its services chapter, and the coverage differs between agreements. The dividing line is genuinely awkward for things that can be delivered either way — software, data, digital content, and goods sold with embedded or bundled services — and has been drawn differently in different instruments. Where classification determines which chapter’s rules apply, the answer comes from that agreement’s definitions and scope provisions.
Why this entry carries no source list. The concept generalises; the definition does not. What this term means for your shipment is set by the particular trade agreement’s own text — its origin protocol, its annexes, its tariff schedules — and two agreements can use the same word differently. There is no central authority to cite, and citing one agreement would imply a generality that does not exist. The operative document is the one governing your trade, and it is what a customs authority will read.