The oldest definition of “perfection”, fairly precise and distinguishing the shades of the concept, goes back to Aristotle. In Book Delta of the Metaphysics, he distinguishes three meanings of the term, or rather three shades of one meaning, but in any case three different concepts.
That is perfect:
1. which is complete — which contains all the requisite parts
2. which is so good that nothing of the kind could be better
3. which has attained its purpose.
This video previously appeared on YouTube.
(via The Good Men Project)