Aw yes, now I remember. It was on nlab's category theory page.


>Now the discovery of ideas as general as these is chiefly the willingness to make a brash or speculative abstraction, in this case supported by the pleasure of purloining words from the philosophers: “Category” from Aristotle and Kant, “Functor” from Carnap (Logische Syntax der Sprache), and “natural transformation” from then current informal parlance.

>(Saunders Mac Lane, Categories for the Working Mathematician, 29–30).