1. A usually cylindrical storage container, especially:
   1. A box or can of thin metal or plastic used for holding dry foodstuffs or cooking ingredients, such as flour or sugar.
   2. A small plastic container used for storing a roll of film.
   3. A metal container that holds pressurized gas, as one containing tear gas that explodes on impact or one containing oxygen as part of a breathing apparatus.
2. 1. A metallic cylinder packed with shot that scatter upon discharge from a cannon, formerly used as an antipersonnel round.
   2. Such cylinders, or the shot used in such cylinders, considered as a group.
3. The part of a gas mask that contains the filter for removing toxic agents from the air.

[Latin canistrum, basket, from Greek kanastron, from kanna, reed. See cane.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.