"process or act of forming ideas," 1829; see idea + -ation. Related: Ideational.
As we say Sensation, we might say also, Ideation; it would be a very useful word; and there is no objection to it, except the pedantic habit of decrying a new term. [James Mill, "Analysis of the Phenomena of the Human Mind," London, 1829]
Related: Ideational.
ideality
idealization
idealize
ideally
ideate
ideation
idem
idempotent
identical
identifiable
identification