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

The jewel of the property, however, is undoubtedly the in-ground outdoor pool and hot tub juxtaposed by the surrounding desert foliage and boulder formations. —Audrey Lee, Architectural Digest, 28 May 2026

If a moose charges, people should seek shelter behind large objects like trees or boulders to create an obstacle in its path. —Lauren Penington, Denver Post, 27 May 2026

While rescuers worked amid challenging conditions to remove the boulder, physicians and surgeons at OHSU assembled medical equipment and loaded it onboard a LifeFlight helicopter, the district said. —Louis Casiano, FOXNews.com, 26 May 2026

Use boulders to soften the abrupt transition between hardscape and greenery. —Marisa Suzanne Martin, The Spruce, 21 May 2026

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