SIMILE

A simile is a comparison between two differing objects which requires a leap of the imagination to see the similarity.  The comparison is made obvious and explicit usually by  the use of the words: as or like:
"Her eyes were as blue as a cornflower." Eyes and cornflowers are very different things, apart from their being blue.  If you were to say: "Her eyes are blue like her sister's," you are not using simile as the two sets of eyes are similar and no imagination is needed to see what they have in common.
The word simile is often wrongly spelled: think of it as having the same number of syllables as metaphor and do not omit the middle i.  Or you can think of it as being like the word similar and you will not forget the spelling.