To clear our views of english grammar

Metaphors and similes express similarities between things that are usually very different. I'm sure every language uses this poetic device. Similes are the easiest to spot, since they always contain "like" or "as": "His hair is as greasy as a the Exxon Valdez." "The sky was like a sheet of lead."

"Metaphor" is the more general term and includes similes. But metaphors don't require "like" or "as": "He has the personality of a dial tone." "Her steak was rubber."