Definitions of oh:
part of speech: noun
One
such
exclamation;
as,
full
of
oh's.
Also,
O.
part of speech: interjection
An
exclamation
expressive
of
pain,
sorrow,
surprise,
or
dissent.
part of speech: interjection
An
exclamation
of
wonder,
pain,
or
anxiety.
part of speech: noun
Denoting
surprise,
pain,
sorrow,
etc.