idiom - an expression that means something else aside from the literal meaningex: I only see her once in a blue moonmeaning: I dont see her very muchmetaphor - compares two things usually saying that one thing is the otherex: The exam was a piece of cakemeaning: The exam was very easypersonification - giving life to a lifeless object ex: The grass is dancing in the windsimile - compares two thing using like or asex: The baby's skin is soft like a cotton