1. a double-walled container with a vacuum between the walls, used to store liquids at very low temperatures
Usage: also called a Dewar flask or vacuum flask; named after Scottish scientist James Dewar

Examples

• The laboratory stored liquid nitrogen in a dewar to keep it at extremely low temperatures.
• A dewar flask is commonly used in scientific research to preserve cryogenic liquids.
• The insulated dewar prevented the liquid helium from evaporating too quickly.
• Scientists filled the dewar with liquid oxygen for the experiment.