This document defines allusions and provides examples of common allusions from literature, art, mythology, the Bible, Shakespeare, and pop culture. An allusion is a brief reference to a person, place, thing or idea that is widely known. The purpose is to help readers understand new ideas by connecting them to familiar references. Allusions work best when the reader is already familiar with the source material. The document discusses how allusions from the Bible, Shakespeare, and Greek mythology are very common due to their influence. It provides examples of allusions from films, TV shows, and advertising to illustrate how allusions add deeper meaning.