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boulder

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The definition of a boulder is a large, smooth rock.

(noun)

When you build a retaining wall and use a large rock in the wall, this rock is an example of a boulder.
A rock that has been detached from the earth by erosion or for other reasons and that is free to be moved about is an example of a boulder.

See boulder in Webster's New World College Dictionary

noun

any large rock worn smooth and round by weather and water
Geol. such a rock larger than a cobblestone with a diameter of at least 256 mm (c. 10 in)

Origin: ME bulder, short for bulderston < Scand, as in Swed bullersten, lit., noisy stone < bullra, to roar (akin to bellow) + sten, stone

city in NC Colo.: pop. 95,000

Origin: from the abundance of large rocks there

See boulder in American Heritage Dictionary 4

also bowl·der

noun

A large rounded mass of rock lying on the surface of the ground or embedded in the soil.

Origin:

Origin: Middle English bulder

Origin: , of Scandinavian origin; see bhel-² in Indo-European roots

A city of north-central Colorado northwest of Denver. It is a major Rocky Mountains resort and the seat of the University of Colorado (opened 1877). Population: 91,500.

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