bullet

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A usually metal projectile in the shape of a pointed cylinder or a ball that is expelled from a firearm, especially a rifle or handgun.
• noun Such a projectile in a metal casing; a cartridge.
• noun An object resembling a projectile in shape, action, or effect.
• noun Printing A heavy dot (•) used to highlight a particular passage.

from The Century Dictionary.

• noun A small ball.
• noun Specifically—2. A small metallic projectile intended to be discharged from a firearm: commonly limited to leaden projectiles for small arms.
• noun In heraldry, a roundel sable (that is, a black circle), supposed to represent a cannon-ball.
• noun In poker, an ace: as, a pair of bullets.

from the GNU version of the Collaborative International Dictionary of English.

• noun A small ball.
• noun A missile, usually of lead, and round or elongated in form, to be discharged from a rifle, musket, pistol, or other small firearm.
• noun obsolete A cannon ball.
• noun The fetlock of a horse.
• noun See Bully tree.
• noun the wood of the bullet tree.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A projectile, usually of metal, shot from a gun at high speed.
• noun Ammunition for a sling or slingshot which has been manufactured for such use.
• noun typography A printed symbol in the form of a solid circle, (•), often used for marking items in a list. (see also bulleted)
• noun informal An entire round of unfired ammunition for a firearm, including the projectile, the cartridge casing, the propellant charge, etc.
• noun banking, finance A large scheduled repayment of the principal of a loan; a balloon payment.
• noun A rejection letter, as for employment, admission to a school or a competition.
• noun slang One year of prison time
• noun slang An ace (the playing card).
• noun figuratively Anything that is projected extremely fast.
• noun Very fast (speedy).
• noun obsolete A small ball.
• noun obsolete A cannonball.
• noun obsolete The fetlock of a horse.
• verb transitive, informal To draw attention to (text) by, or as if by, placing a graphic bullet in front of it.
• verb intransitive, informal To speed, like a bullet.
• verb transitive, informal To make a shot, especially with great speed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a projectile that is fired from a gun
• noun (baseball) a pitch thrown with maximum velocity
• noun a high-speed passenger train