megalith Meaning, Definition & Usage

  1. noun memorial consisting of a very large stone forming part of a prehistoric structure (especially in western Europe)
    megalithic structure.

WordNet

Meg"a*lith noun
Etymology
Mega- + -lith; cf. F. mégalithe.
Definitions
  1. A large stone; especially, a large stone used in ancient building. -- Meg`a*lith"ic a.

Webster 1913