metaphor : a figure of speech which involves an implied comparison between two relatively unlike things meant to illuminate truth.
direct metaphors use "is" to make the comparison explicit. implied metaphors suggest the comparison.
e.g 1) the road was aribbon of moonlight.
2) life is a trap and people are its victims.
N.B the comparison is not announced by "like" or "as". because "like" , "as" , "such as" indicates simile...you have to differntiate between them...
simile means: a figure of speech which involve a direct comparison between two unlike things, usually with the words "like" or "as"
eg.1) as red as blood
2) the muscles on his brawny arms are strong as iron bands