1. noun
a) The exchange or buying and selling of commodities; especially the exchange of merchandise, on a large scale, between different places or communities; extended trade or traffic.
Fifteen years of thought, observation, and commerce with the world had made him [Bunyan] wiser.
b) Social intercourse; the dealings of one person or class in society with another; familiarity.
2. verb
a) To carry on trade; to traffic.
Beware you commerce not with bankrupts. -B. Jonson.
b) To hold intercourse; to commune.
Commercing with himself. -Tennyson.
Wikipedia foundation.