Meaning

noun vacuum flask that holds liquid air or helium for scientific experiments

noun Scottish chemist and physicist noted for his work in cryogenics and his invention of the Dewar flask (1842-1923)

originFrom Scottish Gaelic deòradh (“pilgrim, stranger”), an occupational surname for a custodian of holy relics. It could also be an habitational surname, from Dewar, Scottish Borders. The flask is named for James Dewar, who is credited with its invention.

Etymology from Wiktionary, CC BY-SA 3.0