boul·​der | \ˈbōl-dər \
variants: or less commonly

Definition of boulder 

(Entry 1 of 2)

: a detached and rounded or much-worn mass of rock


geographical name
Boul·​der | \ˈbōl-dər \

Definition of Boulder (Entry 2 of 2)

city northwest of Denver in north central Colorado population 97,385

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Other Words from boulder


bouldered \ˈbōl-​dərd \ adjective
bouldery \ˈbōl-​d(ə-​)rē \ adjective

Examples of boulder in a Sentence

Recent Examples on the Web: Noun

Finally, the Moon landing is arresting, properly showing the tension surrounding the Lunar Module's declining fuel levels, the unexpected field of boulders, and the uncertainty of landing upon an unknown surface. Eric Berger, Ars Technica, "First Man is a first-rate movie about America’s most revered astronaut," 12 Oct. 2018 In addition, there were reports of boulders falling into a park in Hilo on the east side of the island, Okabe said. Jennifer Sinco Kelleher, Fox News, "Hurricane Lane unleashes rain as it shifts closer to Hawaii," 24 Aug. 2018 Although many of the boulders on the peak looked as though they had been split in half by a giant cleaver, a big hunk of Potato Chip Rock is missing, leaving a thin flake hanging above a drop-off. Brian E. Clark,, "Two scenic San Diego hikes, mountaintop and seaside," 24 June 2018 But overall, the southern end of the conduit saw massive buildups of boulders and rubble. William J. Broad, New York Times, "How the Ice Age Shaped New York," 5 June 2018 But the advancing molten rock — and the potential for future eruptions and ejections of boulders — threatens more than the homes. Breena Kerr, Washington Post, "Volcanic activity threatens Hawaii geothermal plant long at center of resident concerns," 11 May 2018 Authorities in California rushed to a teen’s aid on Wednesday after the boy was struck by a boulder, resulting in his arm becoming partially detached from his body, a report said. Elizabeth Zwirz, Fox News, "Teen in California gets trapped beneath boulder, arm partially severed, report says," 18 July 2018 Large boulders, a rock water feature and a gravel semi-circle path link the driveway to a wide brick front patio where there once was grass. Janet Eastman,, "Home-selling etiquette: Lake Oswego homeowner's letter to neighbors (photos)," 8 June 2018 The other is edged by a high, steep, rocky bank, and the water there is perhaps 20 feet and peppered with submerged boulders, some the size of trucks. Shannon Tompkins, Houston Chronicle, "Catch the good times rolling on the rivers," 12 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'boulder.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of boulder


1607, in the meaning defined above

History and Etymology for boulder


short for boulder stone, from Middle English bulder ston, partial translation of a word of Scandinavian origin; akin to Swedish dialect bullersten large stone in a stream, from buller noise + sten stone

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Statistics for boulder

Last Updated

13 Dec 2018

Look-up Popularity

Time Traveler for boulder

The first known use of boulder was in 1607

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More Definitions for boulder



English Language Learners Definition of boulder

: a very large stone or rounded piece of rock


boul·​der | \ˈbōl-dər\

Kids Definition of boulder

: a very large rounded piece of rock

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More from Merriam-Webster on boulder

Rhyming Dictionary: Words that rhyme with boulder

Spanish Central: Translation of boulder

Nglish: Translation of boulder for Spanish Speakers

Britannica English: Translation of boulder for Arabic Speakers Encyclopedia article about boulder

Comments on boulder

What made you want to look up boulder? Please tell us where you read or heard it (including the quote, if possible).


a knickknack or trinket

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