If I eat it at lunchtime (noon) its lunch. If I eat at dinner time (5:00 - 8:00 pm) it's dinner. If I eat it at suppertime (after 9:00 pm) it's supper.
Doesn't matter what the food is or what it's served on - what matters is the time of day it is eaten.
For us, it’s breakfast, dinner (noon) and supper (evening meal). Anything past the dinner was a snack. Supper was/is always served when the men finish working- either 6 or so or dark (for the farmers/rancher) I was going San Marcos Tx on the train (to have a two month stay waiting for our 3rd grandbaby) and met a little 9-10(?) year old black boy from Chicago who was traveling with his grandmother to San Antonio to see relatives. I said something to him about what he was going to eat for supper. He had no idea what I was talking about and when I explained that is what we call dinner, he was tickled and laughed at me. I like to have never gotten away from him. He sat and talked with me most of the trip to San Marcos/San Antonio. He was so proud of his big brothers and cousins who were gang bangers and that is what he aspired to (guns and all that)I believe he was a troubled sad little boy since he sat staring out the window and talked about not liking the zoo - too boring.