It can also be used to refer to the place where people wait before they appear in public even if they are not going to perform. This quote refers to the public drama aspects of the draft of American college football players into the National Football League:

• “Mr. Rodgers was one of six players who began the draft waiting in the famed green room, leading to a wry note from the Cal QB: ‘When we were joking around about putting some money in a pool or something to see who the last guy would be in the green room, it was funny. But it’s not so funny when you’re the last guy in the green room.’”—Carl Bialik and Jason Fry, “Rodgers, Castillo, and Clarett Are Three Draft-Day Surprises,” The Wall Street Journal, April 25, 2005.

The term can also be spelled “greenroom” (one word):

• “Author, who generally sleeps till noon, is at television studio before 8 a.m. Seated in barbershop-type chair in secret makeup chamber, she is powdered, painted, blowdried. Sees in mirror Aschenbach in Death in Venice. In greenroom, Author is introduced to fairy godmother: Ann Patchett in glamorous black dress.”—Cynthia Ozick, “Lighting Out for the Territory,” The New York Times Book Review, January 2, 2005, p. 7.