BANDWAGON

bandwagon

(noun) a large ornate wagon for carrying a musical band; “the gaudy bandwagon led the circus parade”

bandwagon

(noun) a popular trend that attracts growing support; “when they saw how things were going everybody jumped on the bandwagon”

Source: WordNet® 3.1

Etymology

Noun

bandwagon (plural bandwagons)

A large wagon used to carry a band of musicians in a parade.

(figuratively) A current movement that attracts wide support.

Source: Wiktionary