Tone

Definition: Tone is an element of poetry, the way the reader or the poet read the poem that show mood and emotion.

Ex: when the poem have the line: "I will kill you". So the way the poet or the reader read it will show that if that character meant to kill someone, or it's just a joke. When he meant what he said, he will scream the line out loud or murmur it in a low, even voice. But if it's just a joke, he will laugh as he read the line.
Signification: tone will help us understand the message, prevent misunderstand while reading the poem.