Hi Ereshkigal Botanicus Rookie Student,
let's try it the other way around
What is that: It grows on a plant, comes from a blossom and has smaller or larger grains inside that can turn into new plants? Botanically that's a fruit. In the kitchen it might be called a vegetable (though I never quite understand why), but botanically it's a fruit. So are chiles, by the way.
EDIT: This view is supported by the following excerpt from "Tommatial" by our favourite band:
Tommatial is a fruit from the Solanacae
And for the reason of that (he is) poisonous while green.
He's a son of the garden
With a tint of Lycopene
...
Cheers!
Markus