0 used to express different emotions, such as surprise, disappointment, and pleasure, often as a reaction to something someone has said: --
1 sometimes used in writing for the number zero: --
2 written abbreviation for the US state of Ohio: used in addresses --
3 used to express a variety of emotions, such as surprise and pleasure, often as a reaction to something someone has said: --
What was I talking about - oh yes, I was telling you what happened at the party.
You won't catch Carla eating in a cheap restaurant, oh no.
I really didn't want to go away this weekend but, oh well, it can't be helped.
Did you hear what happened to Anna yesterday - oh, speak of the devil, here she is.