boulder

noun

boul·​der ˈbōl-dər 

variants or less commonly bowlder

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

bouldered

ˈbōl-dərd 

adjective

bouldery

ˈbōl-d(ə-)rē 

adjective

Examples of boulder in a Sentence

Recent Examples on the Web

Spectators stopped to take photos, bicyclists and walkers carefully navigated the beach trail littered with rocks and mud, while county workers scooped up the pebbles and larger boulders tossed into the beachfront parking lot by the ocean. —Laylan Connelly, Oc Register, 7 Nov. 2025

To recognize their donations, boulders with plaques on them were unveiled at each end of the bridge. —Ashley MacKin Solomon, San Diego Union-Tribune, 6 Nov. 2025

In the fall, Hempstead recommends hiking just beyond Chester Lake to Elephant Rocks, a grouping of huge limestone boulders surrounded by coniferous trees called larches, whose soft needles turn buttery yellow in late September. —Lisa Kadane, Travel + Leisure, 2 Nov. 2025

At the summit, the landscape is Gothic—like Frankenstein’s monster might be hiding around a boulder. —Lucy Kehoe, AFAR Media, 31 Oct. 2025

Word History

Etymology

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

First Known Use

1607, in the meaning defined above

Rhymes for boulder

• bolder
• bowlder
• colder
• folder
• golder
• holder
• molder
• moulder
• older
• polder
• shoulder
• beholder

Kids Definition

boulder

noun

boul·​der ˈbōl-dər 

: a large detached and rounded or worn mass of rock

Geographical Definition

Boulder

geographical name

Boul·​der ˈbōl-dər 

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