late 14c., "path, track, course of action," introduced by the Hanse merchants, from Middle Dutch or Middle Low German trade "track, course" (probably originally of a ship), cognate with Old English tredan (see tread (v.)).

Sense of "one's habitual business" (1540s) developed from the notion of "way, course, manner of life" (mid-15c.); sense of "buying and selling, exchange of commodities" is from 1550s. Meaning "act of trading" is from 1829. Trade-name is from 1821; trade-route is from 1873; trade-war is from 1899. Trade union is attested from 1831. Trade wind (1640s) has nothing to do with commerce, but preserves the obsolete sense of "in a habitual or regular course."

1540s, "to tread a path," from trade (n.). Meaning "to occupy oneself (in something)" is recorded from c. 1600. Meaning "to barter" is by 1793. The U.S. sports team sense of "to exchange one player for another" is attested from 1899. Related: Traded; trading. To trade down is attested from 1942; trade up from 1959. Trade places "exchange situations" is from 1917. Trading post is recorded from 1796. Trading stamp, given by merchants and exchangeable for goods, is from 1897.

also tradeoff, "sacrifice of one benefit for another," 1959, from verbal phrase to trade off; see trade (v.) + off (adv.).

1917, in reference to used cars, from verbal phrase, from trade (v.) + in (adv.).

also trade-mark, 1838 (the thing itself is attested continuously from 14c., apparently the originals were watermarks on paper), from trade (n.) + mark (n.1) in a specialized sense of "stamp, seal, brand, etc. placed upon an article top indicate ownership or origin" (mid-13c.).

Figurative use by 1869. As a verb, from 1899 (trade-marked). Related: Trademarked; trademarking. This sense of mark also yielded the meaning "particular brand or make of an article" (1660s), hence its use in 20c. names of cars, etc., Mark I, Mark II, etc.

"the business of procuring human beings and taking them to a distant country to sell as slaves," 1734, from slave (n.) + trade (n.).

1590s, from genitive of trade (n.) + man (n.).

"dealer, trafficker, one engaged in commerce," 1580s, agent noun from trade (v.).

1530s, "social intercourse;" 1580s, "interchange of goods or property, trade," especially trade on a large scale by transportation between countries or different parts of the same country, from French commerce (14c.), from Latin commercium "trade, trafficking," from com "with, together" (see com-) + merx (genitive mercis) "merchandise" (see market (n.)). It also was the name of a card game very popular in 1770s and '80s. As a verb, "have dealings with," 1590s. Related: Commerced, commercing.

1680s, "engaging in trade," from commerce + -al (1). Meaning "done for the sake of financial profit" (of art, etc.), "prepared for the market or as an article of trade" is from 1871. Meaning "paid for by advertisements" (in reference to radio, TV, etc.) is from 1932. Related: Commercially.