Answer:

sro

Answer	Crossword Clue
SRO	Capacity-crowd letters
SRO	Full house, in short
SRO	Sellout sign

SRO	Smash letters
SRO	B'way hit sign
SRO	Full house sign
SRO	Packed-performance inits.
SRO	B'way sign
SRO	Hit sign
SRO	Sign at the Bijou
SRO	Welcome sign to a promoter

SRO	"No seats" sign
SRO	Type of housing regulated by HUD
SRO	Sign of success
SRO	Sign of a smash
SRO	Hit-show sign
SRO	Sellout notice
SRO	Sign in a box office
SRO	Sign of a sellout

SRO	Stadium sign
SRO	"No seats left"
SRO	"No more seats" sign
SRO	Sign at a popular show
SRO	Good sign for scalpers
SRO	Packed-house sign
SRO	"No more seats!"
SRO	Full-house sign

SRO	"Sold out" letters
SRO	Packed, for short
SRO	"No seats"
SRO	Sell-out letters
SRO	Sign of a blockbuster?
SRO	Sign of good attendance?: abbr.
SRO	Like well-attended concerts: Abbr.
SRO	Full-house letters

SRO	B'way posting
SRO	Hit indicator
SRO	Success sign
SRO	Ticket buyer's alert
SRO	Full-house sign: Abbr.