“Chainstaurant” (chain + restaurant) is an infrequently used portmanteau. “Our friendly neighbourhood box-store chainstaurant” was cited in print in 2006.
 
   
fancy feast
Sunday, July 23, 2006
Some more advice from Tabby:
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COMMENTS
Anonymous Pesto said…
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So CG-Cat and I gorged ourselves on the Chicken and Rib combo platter at our friendly neighbourhood box-store chainstaurant. And that was almost the end of our night of insanity…
4:11 PM
 
So Soo Mi
Buffalo blues
Posted by Soo Mi   at 5/20/2008 03:10:00 PM  
Today I had lunch at a new chainstaurant called “Buffalo Wild Wings.” It’s just another sports grill, but with a metric assload of wing flavors available, including a few that seemed, well, unpossible.
 
Yelp
“Chainstaurants” that don’t suck
(First entry 7/25/09.—ed.)
Chain Restaurants that (despite being a chain), have been good to me and I enjoy. Food and service have to be good to fit in here! A solid reliable experience is required! Restaurants in this list are location specific—not brand specific 😉 Enjoy! 😊 Criteria for List: No less than 4 stars Never experienced bad service @ the location.
 
Voice Places
8 Ways to Really Piss Off Vegetarians and Vegans
By Voice Places Tue, Jul 2 2013
Chainstaurant Red Robin recently drew the ire of vegans and vegetarians nationwide with a stupid new commercial that mentioned the restaurant’s meatless burger — you know, “just in case your teenage daughter is going through a phase.”
 
Twitter
Dan Seifert
@dcseifert  
chainstaurant: (n) a restaurant that is a chain. portmanteau of “chain” and “restaurant”. Ex: Chili’s, TGI Friday’s, Olive Garden.
8:56 AM - 13 Sep 13