To engage in trade.
This company trades (in) precious metal.
To be traded at a certain price or under certain conditions.
Apple is trading at $200.
To give (something) in exchange for.
Will you trade your precious watch for my earring?
To give someone a plant and receive a different one in return.
To do business; offer for sale as for one's livelihood.
To have dealings; to be concerned or associated (with).