n. A graphical representation, either in the form of an image or made up of ASCII characters, of a particular emotion of the writer.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a representation of a facial expression (as a smile or frown) created by typing a sequence of characters in sending email
Word Usage
"Being such a social networking savvy person, you may know what the term emoticon means - it's a textual expression representing the face of a writer's mood or facial expression."