button cell

noun

variants or button cell battery or button battery

: a small, round, flat battery typically used in watches or other small electronic devices (such as hearing aids)

Part of the discussion at the forum centered on ways area residents can help curb mercury emissions by avoiding throwing away products that contain mercury—thermometers, button cell batteries, fluorescent lights, and the like—into the trash.

—Matt Gunderson, Boston Globe, 13 Dec. 2007

Word History

First Known Use

1970, in the meaning defined above

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!