Ohayou gozaimasu means "Good morning." You use this polite greeting when you meet someone in the morning, typically before noon. It's suitable for friends, family, and colleagues. For example, if you meet your teacher in the morning, you can say, "先生、おはようございます！" (Sensei, good morning!).

朝に人に会ったときに使う丁寧な挨拶です。午前中に使います。「先生、おはようございます！」