One of the many things in this world that cannot be defined unless utilizing some complicate theory (ex: the meaning of life)

The purpose of meaning:
meaning is the "essence" of an object, place, person, term, action, thing, group, ideoligy, etc...
if a term is to have no essence that would render that term useless.

As a retorical question it means "I dont know"

When you eat dirt for the first time and leave your family to build a shack in the woods