There is another use of the word apostrophe, however, that should not be confused with the punctuation mark of the same name.
It is also a literary device, a figure of speech used in a wide range of different literary forms and even in everyday situations.
Coming from the Greek meaning ‘turning away’, it represents the speaker or (in the case of a poem) author figuratively ‘turning’ to address a third party. Usually, in poetry, this third party is something that cannot answer back: an inanimate object, the moon or an abstract idea, perhaps.
It is often marked by a vocative ‘Oh!’ at the beginning, just to make sure the reader is awake.
Examples of apostrophe in poetry
Busy old fool, unruly Sun,
Why dost thou thus,
Through windows, and through curtains, call on
Must to thy motions lovers’ seasons run?
Saucy pedantic wretch
John Donne’s The Sun Rising
And from Macbeth:
Is this a dagger which I see before me,
The handle toward my hand?
Come, let me clutch thee!
I have thee not, and yet I see thee still