boulder
UK: ˈbəʊldə | US: ˈboʊldər
n. a large rounded rock, typically one weathered and smoothed by erosion
The word "boulder" originates from Middle English bulder or boulder, derived from Scandinavian roots (compare Swedish bullersten, meaning "noisy stone," from bullra "to roar" + sten "stone"). The term reflects the rounded, water-worn appearance of such rocks, often found in riverbeds or glacial deposits. The suffix "-er" is a common English nominalizer, though its role here is more historical than functional.
The hikers rested on a massive boulder by the river.
Glaciers transported these boulders across the valley.
The trail was blocked by a fallen boulder after the landslide.
Children climbed the smooth boulder at the park.
The artist carved a sculpture from a single granite boulder.