ideal (adj.) Look up ideal at
early 15c., "pertaining to an archetype or model," from Late Latin idealis "existing in idea," from Latin idea in the Platonic sense (see idea). Senses "conceived as perfect; existing only in idea," are from 1610s. Ideagenous "generating ideas" (1839) is a word from early psychology, apparently coined by Dr. Thomas Laycock, house surgeon to York County Hospital ["Edinburgh Medical and Surgical Journal," vol. 52].
ideal (n.) Look up ideal at
"(hypothetical) perfect person, thing, or state," 1796, in a translation of Kant, from ideal (adj.). Hence "standard or model of perfection" (1849).