Oh (interjection)

1. Used to express a range of emotions including surprise, pleasure, or disappointment.
2. Used to draw attention to something.

Origin:

Late 16th century; earliest use found in william shakespeare (1564–1616). from oh, o + h.

Examples:

1. Oh, that's great news!
2. Oh, I see what you mean.
3. Oh no, I forgot my keys.
4. Oh, look at the time!
5. Oh, I"m sorry. I didn"t mean to hurt your feelings.