[junkbit]

Bananas ARE berries, so are watermelons and tomatoes. But strawberries and raspberries are not berries.

Berries have seeds on the inside; a strawberry's seeds are on the outside, and raspberries are little clusters they are called something else. It's a famous quiz question in the UK :)

[vacri]

It depends, of course, if you're talking as a botanist or as a cook. It's one of those words with multiple levels of truth.

Same with tomato - it's a fruit botanically, but in culinary terms it's a vegetable and definitely not a fruit. As long as you get your context right, you won't have problems communicating :)