1. relating or belonging to or serving as a monument

- the use of the arch in monumental architecture

- monumental sculptures

2. of outstanding significance

- Einstein's monumental contributions to physics

Similar word(s): important, significant

3. imposing in size or bulk or solidity

- a monumental scale

Similar word(s): big, large, massive, monolithic

Sentences with monumental as an adjective:

- "a monumental task"