Sign of a Broadway hit

• Low-cost accommodations, briefly
• Sign of a hit show
• Sign of a sell-out
• "No more seats!"
• Sellout show inits
• Sign of a full house
• Great sign for a Broadway angel
• Pleased producer's placard
• "Seats sold out" sign

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1941, initialism (acronym) for standing room only.