Symbol

Definition: A symbol is something such as an particular mark 
                       that represents some piece of information.


Example: Rose, thou art sick!
The invisible worm
That flies in the night,
In the howling storm,
Has found out thy bed
Of crimson joy:
And his dark secret love
Does thy life destroy.


Significance: A literary or contextual symbol can be a
setting, character, action, object, name, or anything else 
in a work that maintains its literal significance while suggesting other meanings.