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

Rocks and boulders in and along creeks will often be slippery from years of erosion. — Jaclyn Cosgrove, Los Angeles Times, 17 Sep. 2026

In the mountains on the North Carolina-Tennessee border, rains of up to 30 inches (76 centimeters) turned usually gentle streams into torrents that moved trees, boulders, homes and vehicles, and shattered century-old flood records. — ABC News, 16 Sep. 2026

The cellar had been hacked out of granite boulders and wouldn’t budge. — Adriane Quinlan, Curbed, 11 Sep. 2026

Dealing with pests in the garden can sometimes feel like a lifetime of hitting boulders with a banana. — Paul Cappeillo, Louisville Courier Journal, 11 Sep. 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