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Added 9 October 2026

boulder

/ˈbəʊl.də(ɹ)/ noun

noun Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about boulder at Wordnik → Where our words come from →

A large mass of stone detached from the surrounding land.
A particle greater than 256 mm in diameter, following the Wentworth scale
A large marble, in children's games.

verb

To engage in bouldering.

Origin

From late Middle English bulder, short for Middle English bulder ston (“a stone that's been worn into a round shape, boulder, cobblestone”), possibly from Old Swedish *buldersten, itself possibly from Old Swedish bulder (“rumble, noise”) + sten (“stone”); whence dialectal Swedish bullersten (“large stone in a stream, causing water to roar around it”). The first element may alternatively be allied to Old Swedish bulle, bolle (“round drinking vessel, tumbler”), from Old Norse bolli, related to Old English bolla (“round object, bowl”), see English bowl.

From Wiktionary, via Kaikki.org (CC BY-SA)

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