is a literary device in which someone directly addresses an inanimate object or someone who is either dead or simply not there. Apostrophes can be used to heighten one's understanding of a character's emotions, whether positive or negative.
Perhaps the most famous apostrophe in Macbeth is Lady Macbeth's delusional lines in Act V, Scene 1, "Out, damned spot! Out, I say!" In this apostrophe, Lady Macbeth is directly addressing the spots she imagines on her hands, but playgoers recognize the effect of emotional trauma brought on by her participation in King Duncan's murder.
Another famous and emotional apostrophe appears in Act II, Scene 1, as Macbeth struggles with his decision to murder King Duncan:
"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.
Art thou not, fatal vision, sensible
To feelings as to sight? Or art thou but
A dagger of the mind, a false creation
Proceeding from the heat oppresséd brain?
I see thee yet, in form as palpable
As this which I now draw."