Wordnet 3.0
ADJECTIVE (1)
1. 
 (of securities) not traded on a stock exchange; 
- Example: "over-the-counter stocks"[syn: over-the-counter, otc]
WordNet (r) 3.0 (2006):
otc
    adj 1: (of securities) not traded on a stock exchange; "over-
           the-counter stocks" [syn: over-the-counter, otc]