organum

noun

1. (countable, uncountable)A type of medieval polyphony which builds upon an existing plainsong.
2. (archaic, countable, uncountable)A method by which philosophical or scientific investigation may be conducted.

   “He [Francis Bacon] has given us an organum of a different origin and construction from that of Aristotle[…]”

   “Another important circumstance respecting our transcendental esthetics is, that it does not insinuate itself merely as a plausible hypothesis, but is as certain and indubitable as we can require any theory to be in order to serve as an organum.”