char·a·banc 
(shărə-băng′)
(shărə-băng′)n.
Chiefly British
Chiefly British
A bus typically used for sightseeing, originally open and pulled by horses.
[From French char à bancs : char, coach, carriage (from Old French, cart; see CHARIOT) + à, with (from Latin ad, toward; see AD-) + bancs, benches, pl. of banc (from Old French; see BANK3).]
charabanc