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

That was the case with hydraulic mining in the West, which involved aiming a torrent of water under high pressure to blast away soil and boulders to expose the underlying gold veins. — Business Columnist, Los Angeles Times, 13 Oct. 2026

Heidelberg Materials' Torrance Quarry is the same mine where a boulder crushed a man to death in September 2025. — Ricky Sayer, CBS News, 8 Oct. 2026

An Oregon man who was trapped under a boulder about the size of a Volkswagen Beetle used his wireless earbuds to place a call for help, the police and the man’s mother said. — Ishani Desai, New York Times, 4 Oct. 2026

Hairpin turns, narrow gaps between boulders and trees, and clouds of dust kept us crawling most of the way up, which was fine with me. — Patricia Doherty, Travel + Leisure, 27 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