momentous
adjectiveUK /məˈmen.təs/
US /moʊˈmen.t̬əs/
Very important and big.
The day she learned to ride a bike was a momentous day for her.
RELATED WORDS
OTHER MEANINGS
2. Having great effect on the future.
The signing of the peace treaty was a momentous event in history.
3. Full of meaning or consequence.
Her decision to move abroad was momentous for the whole family.
4. Marked by serious importance.
The scientists announced a momentous discovery about the ocean.