natura

natura, naturae is a first declension feminine noun, so the plural runs naturae, naturarum, naturis. It is built on the supine stem of nascor, "to be born", plus the abstract suffix -ura, and means at root "the way a thing turns out", the character it is born with.

Two senses run side by side. The individual sense is a person's or a thing's own make-up: natura hominis. The universal sense is Nature entire, the ordering principle of the world, and that is the backbone of Roman philosophical writing: Lucretius called his poem de rerum natura, and the Stoic programme was secundum naturam vivere, to live in accordance with nature. The bare ablative natura means "by nature, innately", as against arte, by training.