boulder
UK[ˈbəʊldə]US[ˈboʊldər]
n
A very large rock or piece of stone, typically one that has been shaped by erosion or weathering.
Etymology
The word 'boulder' entered English from Middle English, specifically from a Scandinavian source akin to the Swedish dialect term 'bullersten'. This compound literally meant "noisy stone," a reference to the roaring sound a large stone makes when tumbling down a stream or hillside. Over time, the first element was shortened and assimilated into the modern English form, losing its explicit connection to sound. The meaning, however, remained focused on a large, rounded stone, particularly one worn smooth by the action of water, highlighting the enduring link between its origin and its typical geological context.
Analysis
The word 'boulder' is a simplex word borrowed from Middle English. Its ultimate origin is likely Scandinavian, related to the Swedish dialect word 'bullersten', meaning 'noisy stone' (from 'bullra', 'to roar' + 'sten', 'stone').
Examples
The hikers rested in the shadow of a massive granite boulder.
The powerful floodwaters moved boulders as if they were pebbles.
The landscape was dotted with glacial erratics—huge boulders deposited by ancient ice sheets.