Natura naturans is a Latin tag coined during the Middle Ages, meaning "Nature naturing", or more loosely, "nature doing what nature does". The Latin, naturans, is the present active participle of naturo, indicated by the suffix "-ans" which is akin to the English suffix "-ing." naturata, is the perfect passive participle. These terms are most commonly associated with the philosophy of Baruch Spinoza. For Spinoza, natura naturans refers to the self-causing activity of nature, while natura naturata, meaning "nature natured", refers to nature considered as a passive product of an infinite causal chain. Samuel Taylor Coleridge defined it as "Nature in the active sense" as opposed to natura naturata.
The distinction is expressed in Spinoza's Ethics as follows:
[B]y Natura naturans we must understand what is in itself and is conceived through itself, or such attributes of substance as express an eternal and infinite essence, that is … God, insofar as he is considered as a free cause. But by Natura naturata I understand whatever follows from the necessity of God's nature, or from God's attributes, that is, all the modes of God's attributes insofar as they are considered as things which are in God, and can neither be nor be conceived without God.
See also 
- Ethics I P29 Schol. Trans: Edwin Curley. London: Penguin, 1996.