Demonstration doesn't include dinners with fruit (6)
I believe the answer is:
tomato
'fruit' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for tomato that I've seen before include "Love apple (or "beef" fruit?)" , "It's also known as a love apple" , "Red fruit eaten as veg" , ""Plum" or "beef" fruit?" , "Salad fruit or berry" .)