A stage direction term from the theater, referring to the parts of the stage farthest from the audience.

To 'upstage' someone is to step in front of them, forcing them to be more upstage than you; in effect, hiding them or reducing their glory.

Historically, theater stages were tilted slightly towards the audience, so a player who was farther away was actually at a higher elevation.

To "upstage" someone, you would move upstage, that is, move up the raked stage (towards the back wall)-- If you got the other actors downstage of you to then face you, away from the audience, and the attention of both the actors and the audience are now on you.

The term now refers to any means of drawing attention away from someone else. You could upstage someone by moving in front of them, falling down, sneezing, mugging, taking off your clothes, or just being more talented than them.
