Fundamentally these words have lots of reasonable wiggle room to expand or narrow their definitions. Still, lots of technical domains would like to be explicit about what is meant, especially when reusing common words, which is why man invented the glossary.
Unfortunately this hasn't stopped endless argumentation over whether a tomato is a fruit or a vegetable. For whatever reason, it's often presumed that the definition of fruit used in botany has "won", even though botany has nothing to tell us about what a vegetable is or how to distinguish one from a fruit.