First recorded in 1905–10; formerly a trademark
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."
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Add coffee, whether that’s hot in a thermos, iced in a travel mug or purchased from a nearby café on the way to the park, and you’re done.
From Salon • Jun. 18, 2026
In the 1960s and 1970s, he would be up before the sun to pack a thermos of coffee and a camp lunch in one saddle bag and an acrid, tar-like screwworm killer in the other.
From The Wall Street Journal • Jun. 12, 2026
The base fits in cupholders; the handle makes it easier to sip from a heavy thermos while multitasking.
From Slate • Jan. 18, 2024
Hayes also owns the green Stanley thermos, which she takes on hikes and snowshoeing trips with hot cocoa or hot water to stay warm.
From Seattle Times • Jan. 12, 2024
He sat on the bottom stair, opened his thermos flask, and poured some coffee.
From "Black Swan Green" by David Mitchell
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
