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

Some treat your fragile items like King Kong treats boulders. —Marni Jameson, Arkansas Online, 17 Oct. 2025

The mudslide sent rivers of mud, boulders and debris that flattened homes and left 23 people dead in its wake. —Darrell Smith, Sacbee.com, 17 Oct. 2025

Over three hours, small groups navigate a challenging underground world, scrambling over boulders, belly-crawling through narrow passages, and squeezing through tight spaces to discover hidden marble wonders. —Heide Brandes, AFAR Media, 15 Oct. 2025

We were situated in an immense valley peppered with boulders and desert agave plants—the site, Mikkelsen told me, of a winter village of the Kumeyaay people, who have inhabited the region for more than 10,000 years. —Rosecrans Baldwin, Travel + Leisure, 11 Oct. 2025

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