Definition of cracker

• n. - One who, or that which, cracks.
• n. - A noisy boaster; a swaggering fellow.
• n. - A small firework, consisting of a little powder inclosed in a thick paper cylinder with a fuse, and exploding with a sharp noise; -- often called firecracker.
• n. - A thin, dry biscuit, often hard or crisp; as, a Boston cracker; a Graham cracker; a soda cracker; an oyster cracker.
• n. - A nickname to designate a poor white in some parts of the Southern United States.
• n. - The pintail duck.
• n. - A pair of fluted rolls for grinding caoutchouc.