From WordNet (r) 3.0 (2006) [wn]:
seller
n 1: someone who promotes or exchanges goods or services for
money [syn: seller, marketer, vender, vendor,
trafficker]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Seller \Sell"er\, n.
One who sells. --Chaucer.
[1913 Webster]