Compare and contrast is a rhetorical style that discusses the similarities and differences of two or more things: ideas, concepts, items, places, etc. This rhetorical style is one that you’ll see often as a complete essay, but you may also use it quite a lot within paragraphs of any kind of essay in which you need to make some kind of comparison to help illustrate a point.
A compare and contrast essay does two things: It discusses the similarities and differences of at least two different things. First, you must find a basis of comparison to be sure that the two things have enough in common. After that, you identify their differences. You may structure the compare and contrast essay using either the alternating method (stating one aspect of one thing and immediately discussing the same aspect of the other item and how they are similar or different) or the block method (discussing all of the aspects of one thing and then discussing all of the aspects of another).