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

Landscaping with rocks goes beyond gravel—experiment with medium and large boulders to add instant drama to your front yard. —Wendy Rose Gould, Martha Stewart, 20 Feb. 2026

Afterward, experience the twists and turns of Lookout Mountain, which shoots you through big boulders and spits you out on a lazy river. —Stacey Leasca, Travel + Leisure, 18 Feb. 2026

Also planned are an 8- to-10-foot-wide synthetic turf strip, hose bibs, drinking fountains, boulders and log agility features. —Elizabeth Marie Himchak, San Diego Union-Tribune, 17 Feb. 2026

The demonstration involved letting AI set the waypoints, identifying hazards such as sand or boulders. —Tom Chivers, semafor.com, 16 Feb. 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