noun A dry, thin, crispy baked bread (usually salty or savoury, but sometimes sweet, as in the case of graham crackers and animal crackers).
noun A prawn cracker.
noun The final section of certain whips, which is made of a short, thin piece of unravelled rope, or which is a short piece of twisted string tied to the end of the whip, which produces a distinctive cracking sound when the whip is cracked.
noun A firecracker.
noun A Christmas cracker.
noun A northern pintail, a dabbling duck of species Anas acuta.
noun A person or thing that breaks a thing (e.g., nutcracker).