2) A room equipped and furnished for a special function within a business. (i.e. Ice-cream parlor, tanning parlor, gambling parlor, pool parlor)
3) Slang for a brothel or place of prostitution, or a hall or den used in secret to consume narcotics & illegal substances.
"Oh golly! Mr. Whipple down at the ice-cream parlor sure makes a swell milkshake!"
"The parlor got raided by the fuzz; now where'm I gonna get a fix?"