noun

boulder

BOHL-der/ˈbəʊldər/

A large, often rounded rock.

The rounded boulder towers above the nearby ferns.

One massive, naturally rounded boulder resting on a small patch of ground, with tiny grasses and a mature fern at its base providing an immediate sense of scale.

Etymology

boulderMiddle Englishstone worn round, cobblestone

The Middle English expression described a stone worn round, such as a cobblestone. This connection with water-worn stones explains the rounded shape still central to the modern meaning.

In context

National Geographic108:36

The boulder weighs over 550 pounds. It's tough work moving such a heavy object in the cramped and steep corridor. And yet this stone is only a fraction of the weight of the sarcophagi and granite blocks

What Archaeologists Discovered in Ancient Egypt | Lost Treasures of Egypt MEGA Episode | Nat Geo

More examples

Several boulders blocked the path.
He rested beside a boulder.
The stream flowed around the boulder.

Forms

boulder · boulders

Similar words

rock: The broader term, without a large size requirement.
cobble: A smaller rounded stone.