From WordNet (r) 3.0 (2006) [wn]:
Sep
n 1: the month following August and preceding October [syn:
September, Sep, Sept]
From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
SEP
1. Someone Else's Problem.
2. <tool> A SASD tool from IDE.
(1995-10-12)