A figure of speech that makes a direct comparison between two unlike things. A metaphor suggests that one thing IS another thing, or is equal to another thing.
Example From Text
…a single thin ray fell upon the vulture eye.
Here, Poe again compares the old man's eye to the eye of a vulture. This time, instead of saying the eye looks like a vulture's eye, Poe suggests the eye IS a vulture's eye. Can you imagine how this thought in the narrator's mind makes the old man seem less like a person and more like a wild animal?