A bus ( /ˈbʌs/; plural "buses", /ˈbʌsɨz/, archaically also big car, omnibus, multibus, or autobus) is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker rigid bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are used for longer distance services. Bus manufacturing is increasingly globalised, with the same design appearing around the world.

Buses may be used for scheduled bus transport, scheduled coach transport, school transport, private hire, tourism; promotional buses may be used for political campaigns and others are privately operated for a wide range of purposes.

Horse drawn buses were used from the 1820s, followed by steam buses in the 1830s, and electric trolleybuses in 1882. The first buses powered by internal combustion engines were used 1895^{[citation needed]} and this is still the most common power source. Recently there has been growing interest in hybrid electric buses, fuel cell buses, electric buses as well as ones powered by compressed natural gas or bio-diesel.