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

Hikers often spot these charismatic creatures perched on boulders or scurrying through wildflowers. — Brittany Peterson, Fortune, 21 Aug. 2026

Lee also added that crews are clearing sediment and boulders to help prevent dangerous mudslides. — Chelsea Hylton, CBS News, 20 Aug. 2026

The famous oak tree, whose roots split a massive sandstone boulder in half and gave the place its name, has also since died. — Wendy Bowman, Robb Report, 20 Aug. 2026

The space is pristine and remote, surrounded by woods and loons and big muscular-looking boulders for perching on and thinking deep thoughts. — Kathryn Vanarendonk, Vulture, 19 Aug. 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