means The reason something exists or is done — the intention, aim, or function that gives an action or a life its direction.

from From Old French 'porpos' (intention, aim), from the verb 'porposer' — to put forth, propose. That 'porposer' is itself a blend of Latin 'pro-' (forward) and 'ponere' (to place), the same 'place forward' impulse that gives us 'propose' and 'purport.' So at root, purpose is something you set out in front of yourself and walk toward.