WHAT IS AN ALLUSION? PLEASE HELP?

Plain and simple an allusion is a literary reference to something that is not common knowledge. An example of a SONG that uses allusion is Good Charlotte's "Silver Screen Romance" To begin with the title of the song is an allusion because it isn't common knowledge that black and white movie's are also referred to as "Silver Screen Films" as the Chorus goes "You're my Bette Davis, I'm your Cary Grant" this is an allusion because it is not common knowledge that Bette Davis and Cary Grant are famous for acting together in black and white romance flicks, but is being referred to in order to illustrate this couple having an old school romance.