1.
to promise, to make a commitment
To give one's word to do or not do something.
秘密を守ると約束した。
I promised to keep the secret.
約束は守らなければならない。
Promises must be kept.
2.
to make an appointment, to arrange to meet
To agree on a time and place to meet someone.
友達と映画を見る約束をした。
I made plans to see a movie with my friend.
COMMON COLLOCATIONS:
- 約束を守る: to keep a promise
- 約束を破る: to break a promise
- 約束の時間: the promised time, appointment time
USAGE:
In Japanese, 約束 is used both for formal promises/commitments and casual appointments/plans to meet.