1. To make a loud, bawling noise: The cow started to bellow when the farmer was late to milk her.
2. To shout in a deep voice: Kirby was heard to bellow orders to one of his employees.

A device that produces a strong current of air when its sides are pressed together: Emery used a bellows to help him start the fire.

A surge or swell of water, a rolling mass of something; such as, smoke which resembles the movement of water: The billow of smoke on the horizon worried the fire watch.

1. To swell out or to balloon through the action of the wind: The sails on the ship will billow when the wind comes up.
2. To move as a large cloud or mass: Clouds of smoke were seen to billow up from the chimney.