The Collaborative International Dictionary
airgun \air"gun`\, air gun \air" gun`\(g[u^]n`). A kind of gun in which the elastic force of condensed air is used to discharge the ball. The air is powerfully compressed into a reservoir attached to the gun, by a condensing pump, and is controlled by a valve actuated by the trigger. The common BB gun is a type of air gun.
Wiktionary
n. a gun that shoots BB-size pellets, typically using compressed air, or sometimes just a compressed spring.
Wikipedia
BB guns are a type of air gun designed to fire spherical projectiles similar to shot pellets of approximately the same size. Modern BB guns usually have a barrel with a bore and caliber of and are available in many varieties. BB shot for modern BB guns is usually steel, plated either with zinc or copper to resist corrosion, and measure in diameter. Some manufacturers still make lead balls of slightly larger diameter and which are generally intended for use in rifled BB gun barrels.
The term BB gun is often incorrectly used to describe a pellet or air gun. Although in many cases a BB steel ball can be fired in a pellet gun, pellets usually cannot be fired in a gun specifically designed for BBs. However, many air gun models using plastic ammunition allow for use of both types.
Usage examples of "bb gun".
And each generation, of course, owned somebody who had lost an eye to a BB gun.
Which is a valid concern, but they could just say so, instead of hiding behind the BB gun defense.
Not even Keith would go looking for five guys-or even one guy-with nothing but a BB gun.
Billy put down his BB gun and glanced over at the new mailman, curious, but the windows of the red car were tinted, the interior dark, and all he could see was a thin white hand and the sleeve of a blue uniform reaching out from the driver's window to put a stack of letters in the mailbox.
Wilson remembered when he was ten and out shooting birds with a BB gun, he had seen a dead squirrel in the water, floating out from under the bridge, face down, as if it were snorkeling.
He had popped at it and all around it with his BB gun for as long as the gun had the distance.
On my usual Saturdays, I wandered down Manor Street in a black, bored rage, scratching the sides of our neighbors' cars and crouching under a bush to shoot passing dogs with my BB gun.
As a kid, I got shot by a BB gun and slugged by a much bigger boy because I wouldn’.
I'll tell them you got hit by a car, or developed lung cancer from the smog, or got shot in the butt by some spoiled kid with a BB gun.
It reminded Bud of the days of his youth, when, from time to time, one of his playmates would shoot him in the head with a BB gun.