約束 (yakusoku) means 'promise' or 'appointment.' It refers to an agreement made with someone to do something or meet at a certain time. For example, '友達と会う約束があります' (I have an appointment to meet a friend) or '約束を守る' (keep a promise).

「約束」は、人と何かを決めることです。例：「約束の時間」