Neil Simon's favorite letters

• Like a transient's qtrs., maybe
• Affordable housing designation
• "No more seats" letters
• Hit show initials
• Sad letters for latecomers
• Certain hotel, briefly
• 1966 gold album by Herb Alpert & the Tijuana Brass
• Sellout sign: abbr
• Sign of a big hit

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