An exclamation used in calling or directly addressing a person or personified object; also, as an emotional or impassioned exclamation expressing pain, grief, surprise, desire, fear, etc.
“For ever, O Lord, thy word is settled in heaven.”
— Ps. cxix. 89.
“O how love I thy law ! it is my meditation all the day.”
— Ps. cxix. 97.
“
O for a kindling touch from that pure flame!”
— Wordsworth.
“But she is in her grave, -- and
oh
The difference to me!”
— Wordsworth.
“
Oh for a lodge in some vast wilderness!”
— Cowper.
“We should distinguish between the sign of the vocative and the emotional interjection, writing O for the former, and oh for the latter.”
— Earle.