Canteen

A canteen is a type of container used for storing liquids, typically water for consumption.

The archaeologist Gest kept a canteen to drink from, when she began steeling harmonic diamonds from members of an expedition she was participating in she kept them in her canteen. However because of this she stopped drinking from the canteen, a behaviour Jean-Luc Picard noticed which allowed him to discover her crimes. (TNG comic: Captain's Pleasure)