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

Threaded throughout is an even cooler environment to send them back into, whether snowshoeing the gently hilly grounds or admiring the Front Range from a boulder while noting plant and insect species. —John Wenzel, Denver Post, 17 Apr. 2026

People of all ages and skill levels can easily scramble over the massive pink granite boulders here. —Erika Ebsworth-Goold, Travel + Leisure, 12 Apr. 2026

If the object is larger, like a boulder, and brighter, it’s called a bolide or a fireball. —Patrick M. Shober, The Conversation, 10 Apr. 2026

If there are large boulders in the area, all the better. —Joe Cermele, Outdoor Life, 9 Apr. 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 population 97,385