The Collaborative International Dictionary of English v.0.48:

Sebat \Se"bat\, n. [Heb. sh[e^]b[=a]t.]
   The eleventh month of the ancient Hebrew year, approximately
   corresponding with February. --W. Smith (Bibl. Dict.).
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Sebat
   the eleventh month of the Hebrew year, extending from the new
   moon of February to that of March (Zech. 1:7). Assyrian sabatu,
   "storm." (See MONTH.)


Hitchcock's Bible Names Dictionary (late 1800's):

Sebat, twig; scepter; tribe