mountain time

noun

variants often Mountain time
: the time of the seventh time zone west of Greenwich that includes the Rocky Mountain states of the U.S. see time zone illustration

Word History

First Known Use

1883, in the meaning defined above

Time Traveler
The first known use of mountain time was in 1883

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Cite this Entry

“Mountain time.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mountain%20time. Accessed 1 Jul. 2026.

Kids Definition

mountain time

noun
often capitalized M
: the time of the seventh time zone west of Greenwich that includes the Rocky Mountain states of the U.S.
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