A person who lives on Park Avenue—a street known for its wealthy residences—is a “Park Avenuer” or “Park Avenoor.”
     
The term “Park Avenoor” was popularized by Joseph Van Raalte, who wrote a syndicated “Bo Broadway” newspaper column. “Then there’s the Park avenoor who has made friends, unwittingly, with a ‘con lady,’” Van Raalte wrote in the New York (NY) World in February 1922.
 
“Park avenuers” was printed in a 1927 newspaper and “Park Avenuers and Fifth Avenuers” was printed in a 1927 book. The “Park Avenuer” term also sometimes means “rich snob.” However, “Park Avenuer” became less popular after the 1920s and 1930s.
   
   
Wikipedia: Park Avenue
Park Avenue is a wide New York City boulevard[4] which carries north and southbound traffic in the borough of Manhattan. For most of the road’s length in Manhattan, it runs parallel to Madison Avenue to the west and Lexington Avenue to the east. Park Avenue’s entire length was formerly called Fourth Avenue; the title still applies to the section between the Bowery and 14th Street.[5] Meanwhile, the section between 14th and 17th Street is called Union Square East, and between 17th and 32nd Streets, the name Park Avenue South is used.
       
28 February 1922, Denver (CO) Post, “With Cocktails Hard to Get And Harder to Drink, N. Y. Now Gambles for Pastime,” pg. 10, cols. 3-4:
WITH cocktails harder to get and dangerous to take once you get ‘em, New York for excitement has turned enthusiastically to gambling, writes Joseph Van Raalte in the New York World.
(...)
Then there’s the Park avenoor who has made friends, unwittingly, with a “con lady.”
 
1 April 1922, San Antonio (TX) Evening News, “New York Is Gambling Mad,” pg. 4, col. 4:
Then there’s the Park Avenoor who has made friends, unwittingly, with a “con lady.”
 
Google Books
The Jeweled Herd
By Ida M. Evans
New York, NY: J.H. Sears & Co.
1927
Pg. 148:
She laughed again. “That sounds conceited, Professor. Of course I couldn’t. But I’m just as much interested as those Park Avenuers and Fifth Avenuers that flock into the lecture rooms.”
   
4 February 1927, Kansas City (MO) Star, “Looking Stylish by Renting” by Herbert Corey, pg. 36, cols. 2-3:
One would not be surprised at this in a haunt of the Park avenuers, but one is somehow shocked at the extent to which the cigarette has made its way among the women of the bourgeoisie.
 
19 June 1929, Variety (New York, NY), “Chatter in New York,” pg. 58, col. 3:
Wild party of Park Avenuers slumming in Harlem had a novel experience when a pretty brunet member of the revellers was nearly “electrocuted” in one of the lower Nubian drives.
 
6 July 1929, Allentown (PA) Morning Call, “Bo-Broadway” by Joseph Van Raalte, pg. 10, col. 1:
New York, July 5.—A real archduke is about to embark in trade in the Holy City. Naturally, he intends to cater to the wants of the Park Avenoors; but the dollars of the other avenues will not be overlooked.
   
10 August 1929, Allentown (PA) Morning Call, “Bo-Broadway” by Joseph Van Raalte, pg. 10, col. 5:
POOR PARK AVENOORS!
When Park Avenue gets stomach trouble the Big Diamond Doctors in the neighborhood are called in, take on an air of Socratic wisdom and after a lot of palaver and unnecessary hooey, prescribe a “whole wheat diet.”
 
22 April 1932, Evansville (IN) Courier, “On Broadway” by Walter Winchell (During illness of Mr. Winchell this column is being conducted by Paul Yawitz), pg. 8, col. 7:
I have seen more Park Avenuers on the Gland Canyon than on the other side of the Great Social Divide (Sixth Avenue—ed.).
     
11 June 1932, The Afro-American (Baltimore, MD), “New York Society: Taylor Gordon’s Rent Party is Hot,” pg. 3, col. 7:
And what a crowd. All classes and colors met face to face, ultra aristocrats, Bourgeois, Communists, Park Avenuers galore, bookers, publishers, Broadway celebs, and Harlemites giving each other the once over.
 
3 February 1934, The Afro-American (Baltimore, MD), “Social Skits” by William Smallwood, pg. 14, col. 4:
It was there I completed my incomplete task of meeting the New York 400, with many Park Avenuers and B’way big-timers thrown in.
 
Google Books
The Big Sea:
An Autobiography
By Langston Hughes
New York, NY: Alfred A. Knopf
1940
Pg. 243:
All classes and colors met face to face, ultra aristocrats, Bourgeois, Communists, Park Avenuers galore, bookers, publishers, Broadway celebs, and Harlemites giving each other the once over.
 
Twitter
Melissa Mermaid‏
@TweetingMyStory
The well-to-do Park Avenuers were up in arms over a large dept store moving to the UES. Alarmed & concerned about their real estate ...
10:46 AM - 16 Jul 2009
 
Twitter
Liam Taggart‏
@_liamtaggart
Replying to @jmcdermott95
@jmcdermott95 @lauren_saville here you nee to keep an eye on those park avenuer’s! They are as thick as thieves those fuckers!
4:48 PM - 22 Aug 2012