thermos

/ˈθʌrməs/

/ˈθʌməs/

Other forms: thermoses

A thermos is a portable container that keeps liquids hot or cold for a long time. When you go ice skating, you may want to bring along a thermos of hot chocolate.

Officially, the word Thermos is spelled with a capital T, since like Band-Aid and Kleenex, it's actually a trademarked brand name. Still, it's common to refer to vacuum flasks (even those not made by the Thermos company) generally as thermoses. The very first thermos was made in 1892, and they were produced commercially starting in 1904. In Greek, the word thermos means "hot."

Definitions of thermos

1. noun

   vacuum flask that preserves temperature of hot or cold drinks
   synonyms: thermos bottle, thermos flask

   type of:

   vacuum bottle, vacuum flask

   flask with double walls separated by vacuum; used to maintain substances at high or low temperatures