From WordNet (r) 2.0 (August 2003) [wn]:
seller
n : someone who promotes or exchanges goods or services for
money [syn: 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]