What word does your mother always say?
"officer's servant," originally military title for "man in charge of a bat-horse and its load," 1755, from bat "pack-saddle" (late 14c.), from Old French bast (Modern French bât), from Late Latin bastum (see baton). Hence also batwoman (1941). The comic book hero dates from 1939.
A comic strip character that first appeared in 1939. With his faithful sidekick Robin (the Boy Wonder), Batman fights crime in Gotham City, foiling evil villains such as the Joker and the Riddler.
Note: Batman's adventures have been widely adapted for television and a number of motion pictures.