Boulder

Part of speech: noun

Pronunciation: /ˈbəʊl.də(ɹ)/

Definitions

1. A large rounded rock that has been worn smooth by natural weathering or water erosion
2. A sizable rock, typically large and rounded, that can serve as a natural obstacle, geological feature, or aesthetic element in outdoor settings
3. A large, solid mass of stone, often rounded due to erosion, that can be found in nature as a geological feature or as a barrier in landscapes

Etymology: The most striking clue in "boulder" is the sound it once made. Its likely ancestor is Old Swedish "bulder", meaning "rumble" or "noise", paired with "sten", meaning stone. Dialectal Swedish still preserves "bullersten" for a large stone in a stream that makes the water roar as it rushes around it. In other words, the word may have started as a description of a sound rather than a shape. English borrowed it in late Middle English as "bulder", short for "bulder ston", which described a stone worn into a round shape, something like a cobblestone. The rounded form was the original emphasis, and the sense of a massive rock came later. Not everyone agrees on the first element. It may instead be connected to Old Swedish "bulle" or "bolle", a round drinking vessel, which links back to Old English "bolla", a round object or bowl, and so to the English word "bowl". On this reading, the word began with the idea of roundness rather than noise.

Synonyms: rock, stone, boulderstone

Antonyms: pebble, gravel