1855 in theatrical jargon, "to the rear of the stage," from up (adv.) + stage (n.). From 1901 as an adjective, 1916 as a noun. The notion in the verb (1921) is of drawing attention to oneself (and away from a fellow actor) by moving upstage, so that the other actor must face away from the audience. Related: Upstaged; upstaging.
When the dog entered the stage, he upstaged the actress
she crossed to the upstage chair forcing the lead to turn his back to the audience
he was upstage with strangers
the dancers were directed to move upstage
upshot
upside
upside down
upsilon
upskirt
upstage
upstairs
upstanding
upstart
upstate
upstream
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