Meaning

noun the act of caressing with the lips (or an instance thereof)

noun a vehicle carrying many passengers; used for public transport

noun the topology of a network whose components are connected by a busbar

originUncertain. First attested in the 1560s. Possibly from Proto-Indo-European *bʰus- (“lip, to kiss”) via Proto-Germanic *busaną (compare German bussen), but in any case imitative of kissing. Compare Welsh bus (“kiss, lip”) and Irish bus (“lips, mouth”) (both may have influenced English), Persian بوس (bus, “kiss”), Latvian buča (“kiss”), Latin basium (“kiss”). Mainstream proposals like in The Free…

Etymology from Wiktionary, CC BY-SA 3.0