From WordNet (r) 3.0 (2006) [wn]:
batman
n 1: an orderly assigned to serve a British military officer
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Batman \Bat"man\ (b[a^]t"m[a^]n), n. [Turk. ba[.t]man.]
A weight used in the East, varying according to the locality;
in Turkey, the greater batman is about 157 pounds, the lesser
only a fourth of this; at Aleppo and Smyrna, the batman is 17
pounds. --Simmonds.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Batman \Bat"man\ (b[add]"man or b[a^]t"man), n.; pl. Batmen
(b[a^]t"men). [F. b[^a]t packsaddle + E. man. Cf.
Bathorse.]
A man who has charge of a bathorse and his load. --Macaulay.
[1913 Webster]