Technically a pumpkin is a fruit, although in many agricultural regulations it's classified as a vegetable. Governments can't get anything right!
Actually, classifications are interesting and botanists and science decides what is or is not a fruit or vegetable. Usually.
Sometimes, the government decides a vegetable is a fruit for taxation reasons and sometimes, fruits like tomatoes are called vegetables because the public is not up on their horticulture and botany.
What bothers me is the USDA. If ANY part of a tomato is ANY shade of red or even the lightest shade of pink, it can be picked and be legally called "vine ripened" by the grower. Bet you thought vine ripened meant something else.
There are scientific classifications and culinary ones that run up against what we think makes sense. If the edible has seeds, it is a fruit. Even a banana has a seed so it is a fruit. Jalapeno peppers and avocados and string beans and cucumbers are fruits, too.
By the way, in the world of wood, the type of tree tells you if a particular species is a hardwood or softwood. Balsa is extremely soft wood, but it is not a softwood, it is a hardwood.
And glass is technically a liquid, if you were wondering; it is always flowing.