Douglas Harper's Etymology Dictionary
type of restaurant, 1906, American English, from luncheon + diminutive ending -ette.
Wiktionary
n. A small diner or restaurant that serves lunch.
Usage examples of "luncheonette".
Back in Bensonhurst, Sammy returned to robbing with the Rampers, hanging out at their favorite corner luncheonette at 79th Street and Utrecht Avenue.
I told them I would see them at the luncheonette, the usual spot where we used to meet.
Rizzo told me that a friend of his had this luncheonette and was selling it.
I took out two hundred, and went to a luncheonette and had breakfast, surrounded by people eating a late lunch.
Outside, they dashed across Madison to a luncheonette that had not yet filled up with the breakfast crowd.
On the way there she got thirsty and stopped in her favorite luncheonette for an egg cream.
She stopped on her way out of the luncheonette to buy a jumbo chocolate-chip cookie, pocketed the receipt for reimbursement and headed back outside into the sour, desert-dry afternoon.
When she got to Shoshoni, she slowed down and parked in front of a luncheonette.
Remo said, sitting back naked in the mayor's tan leather chair, looking out over a street filled with happy Puerto Ricans, happy luncheonettes and happy record stores.
In Gainesville I thought I'd sleep by the railroad tracks awhile but they were about a mile away and just as I thought of sleeping in the yard a local crew came out to switch and saw me, so I retired to an empty lot by the tracks, but the cop car kept circling around using its spot (had probably heard of me from the railroad men, probably not) so I gave it up, mosquitoes anyway, and went back to town and stood waiting for a ride in the bright lights by the luncheonettes of downtown, the cops seeing me plainly and therefore not searching for me or worrying about me.
I had lunch at the Academy Luncheonette and Sporting Goods Store (possibly the only place in America where you can gaze at jockstraps while eating a tuna salad sandwich) and was intending then to push on in search of the AT, but on the way back to the car I passed a public library and impulsively popped in to ask if they had any information on Centralia.