The Collaborative International Dictionary of English v.0.48:
Shipper \Ship"per\, n. [See Ship, n., and cf. Skipper.] One who sends goods from one place to another not in the same city or town, esp. one who sends goods by water. [1913 Webster]WordNet (r) 3.0 (2006):
shipper n 1: someone who ships goods 2: a company in the business of shipping freight