[scotteric]

Cucumbers and green beans are fruit. Fruit is a botanical term for the structure that a flower grows into once fertilized. Fruit has seeds.

[dekhn]

(and fennel is an herb, which is a vegetable, that makes fruits which have seeds)

[scotteric]

I think fennel seeds are considered a spice in culinary terms. The bulb part I think would be a vegetable in culinary terms.