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

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

In Dana Point, coastal homeowners on Beach Road — part of the Capistrano Bay Community Services District — have been racing to install protection like a boulder barrier, according to a statement from the city. — Los Angeles Times, 28 Sep. 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