minibus
n.a small bus that can carry about 15 to 20 people. It is often used for short trips or to move a small group of people.
n.a small motor vehicle designed to carry a small number of passengers, typically between 15 and 20. Often used for local transport or group excursions.
“The school uses a minibus to take the students on their field trip.”
“We hired a minibus to transport the entire wedding party to the reception venue in the countryside.”
“While the city's main bus network handles the bulk of the daily commuters, a fleet of minibuses provides the essential final-mile connectivity to the more remote residential estates.”
From mini- + bus. In the political sense, probably a back-formation from omnibus.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.