English definition of “oh”
PAUSE › used before you say something, often before replying to what someone has said: "Ian's going." "Oh, I didn't realize." "I'm so sorry." "Oh, don't worry."
EMOTION › used to show an emotion or to emphasize your opinion about something: Oh, no! I don't believe it! "I don't think I can come." "Oh, that's a shame." Oh, how sweet of you!