The Collaborative International Dictionary of English v.0.48:

Sabaoth \Sab"a*oth\ (s[a^]b"[asl]*[o^]th or s[.a]"b[=a]*[o^]th;
   277), n. pl. [Heb. tseb[=a]'[=o]th, pl. of ts[=a]b[=a]', an
   army or host, fr. ts[=a]b[=a]', to go forth to war.]
   1. Armies; hosts.

   Note: [Used twice in the English Bible, in the phrase "The
         Lord of Sabaoth."]
         [1913 Webster]

   2. Incorrectly, the Sabbath.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Sabaoth
    n 1: (plural) hosts or armies; used in the book of Romans in the
         New Testament; "Lord of Sabaoth"

Easton's 1897 Bible Dictionary:

Sabaoth
   the transliteration of the Hebrew word _tsebha'oth_, meaning
   "hosts," "armies" (Rom. 9:29; James 5:4). In the LXX. the Hebrew
   word is rendered by "Almighty." (See Rev. 4:8; comp. Isa. 6:3.)
   It may designate Jehovah as either (1) God of the armies of
   earth, or (2) God of the armies of the stars, or (3) God of the
   unseen armies of angels; or perhaps it may include all these
   ideas.


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

Sabaoth, Lord of hosts