RhymeZone: cryptogenic definitions

Definitions of cryptogenic:

adjective: (of an organism) Of uncertain origin, either introduced or native to its area.
adjective: (of epilepsy) Presumed but not proven to be caused by an abnormality in a particular part of the brain (contrasts with symptomatic and idiopathic).
adjective: (of a disease) Of uncertain cause.

(Definitions from Wiktionary)