or·ga·non 
(ôrgə-nŏn′) also or·ga·num (-nəm)
(ôrgə-nŏn′) also or·ga·num (-nəm)n. pl. or·ga·na (-nə) or or·ga·nons or or·ga·nums
A set of principles for use in scientific or philosophical investigation.
[Greek, tool, organ of the body, instrument; see werg- in the Appendix of Indo-European roots.]