This is quite an open-ended question so it would help if you narrowed it down a bit. 'Mean' can be used as an adjective (someone who is unkind to others), a noun (same as average) and a verb. This is probably what causes your confusion. You might want to take a look at dictionaries that provide some sort of an explanation, like this: http://www.thefreedictionary.com/mean Feel free to ask if you have any questions.