a wagon, usually large and ornately decorated, for carrying a musical band while it is playing, as in a circus parade or to a political rally.
2.
a party, cause, movement, etc., that by its mass appeal or strength readily attracts many followers: After it became apparent that the incumbent would win, everyone decided to jump on the bandwagon.
an extraordinary or unusual thing, person, or event; an exceptional example or instance.
a chattering or flighty, light-headed person.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.
a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.
a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.
1855, Amer.Eng., from band (2) + wagon, originally a large wagon used to carry the band in a circus procession; as these also figured in celebrations of successful political campaigns, being on the bandwagon came to represent "attaching oneself to
anything that looks likely to succeed," a usage first attested 1899 in writings of Theodore Roosevelt.