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

In May, Greenpeace dropped 15 limestone boulders into France’s Golfe du Lion, aiming to physically block bottom trawling in a marine area that has long been designated for protection. —Annika Hammerschlag, Christian Science Monitor, 9 June 2025

At each summer solstice, the light passes across an even larger boulder and touches the center of the spiral. —Emese MacZko, Forbes.com, 6 June 2025

Ben Sharkey, now a visiting senior faculty specialist at the University of Maryland, College Park, led a study published in November 2021 suggesting that the Ferris wheel-size asteroid may be a massive boulder ejected from the moon by an impact. —Ashley Strickland, CNN Money, 28 May 2025

Assist/bdc/boulder A new wildfire was reported 11:27 a.m. —Ca Wildfire Bot, Sacbee.com, 12 May 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