noun, noun or participle which takes 'suru', transitive verb
promise; agreement; one's word; contract
Broad everyday use for a promise or agreement, from a personal promise to a pact or contract-like understanding. Common patterns include 約束する, 約束を守る, and 約束を破る; for a formal legal contract, 契約 is often more precise.
秘密を誰にも話さないと約束した。
I promised not to tell anyone the secret.
約束を守るために、彼は時間どおりに来た。
He came on time to keep his promise.
noun
Used when there is an arrangement to meet or do something with someone. It often appears as 会う約束 or 約束がある, and can include a social date depending on context.
三時に駅で友達と会う約束がある。
I have an appointment to meet a friend at the station at three.
noun
Refers to an agreed-upon convention, rule, or expected pattern within a field, art form, story, or group. In modern Japanese, 約束事 is also very common for this meaning.
歌舞伎には、初めて見る人には分かりにくい約束がある。
Kabuki has conventions that are hard for first-time viewers to understand.
noun, noun or participle which takes 'suru', transitive verb
Rare and literary or old-fashioned as a noun meaning fate or something ordained. Modern everyday Japanese usually uses 運命 or 定め instead for this meaning.
古い文章では、約束が「運命」や「定め」に近い意味で使われることがある。
In older writing, 約束 is sometimes used with a meaning close to 'destiny' or 'fate.'