Definition of trade:
(adj) :
relating to or used in or intended for trade or commerce; "a trade fair"; "trade journals"; "trade goods"
(n) :
the commercial
exchange (buying and selling on domestic or international markets) of goods and services; the collective people who perform a particular kind of skilled work; "he represented the craft of brewers"; "as they say in the trade"
(v) :
to engage in the trade of; to be traded at a certain price or under certain conditions; as in stock trade
"will you trade your precious watch for my earring?"