The scientific definition of a berry is a fleshy fruit that came from a single ovary in the flower. Thats it. I don't even know why they used the name berry on this term because it makes no sense and I tell you this as someone studying botany. Like none of the nuts you know are true nuts either. If a nuts shell opens on its own it's not a nut so peanuts, walnuts and almonds are not nuts because if you plant these in fresh soil they will sprout and the shell opens. However if you plant a fresh hazelnut the shell stays on while the plant germinates from the seed, hence it's a true nut. So stupid I know. This has use in botany but these botanical definitions have no use for normal people. That's why we talk about "botanical definitions" and "culinary definitions". In the common culinary definition a berry is a small freshy fruit which is the definition you know.

Bonus: in botany everything from a flower is a fruit. That means wheat is a fruit, rice is a fruit, beans are fruits, peas are fruits, all nuts are fruits, every seed is a fruit, a pine cone is a fruit, and it just goes on. But no one in their right mind would make a fruit asket with pine cones right? The botanical definition is useless outside the field of botany.