ideagenous,a.|aɪdiːˈædʒɪnəs| [irreg.f. idea + -genous. (The etymological form would be ideogenous.)] Producing or giving rise to an idea. 1881Huxley Sc. & Cult. ix. 235 Each sensory impression leaves behind a record in the structure of the brain—an ‘ideagenous’ molecule, so to speak.