n.
Variant: also O
Pronunciation: ( ' ) ō
Function: interjection
Etymology: Middle English o
Date: 13th century
1 ― used to express an emotion (as surprise or desire) or in response to physical stimuli
2 ― used in direct address < oh , waiter! Will you come here, please?>
3 ― used to express acknowledgment or understanding of a statement
4 ― used to introduce an example or approximation