Symbol

Definition:

A symbol is something that represents more than itself. In poetry, writers often use symbolism to express hidden and important ideas.

Example:

"We slowly drove—He knew no haste
 And I had put away
 My labor and my leisure too,
 For His Civility—"
--"Because I Could Not Stop For Death" by Emily Dickson

In this poem, "he" is a personified symbol of Death.

Significance:

Symbol is important in poetry because it represents ideas more than itself. This makes the poem more interesting and lets people to find the true meaning of it if they looked deeper.