1. Existing in idea or thought; conceptional; intellectual; mental; as, ideal knowledge.
2. Reaching an imaginary standard of excellence; fit for a model; faultless; as, ideal beauty. There will always be a wide interval between practical and ideal excellence. (Rambler)
3. Existing in fancy or imagination only; visionary; unreal. Planning ideal common wealth.
4. Teaching the doctrine of idealism; as, the ideal theory or philosophy.
5. (Science: mathematics) imaginary.
Synonym: Intellectual, mental, visionary, fanciful, imaginary, unreal, impracticable, utopian.
Origin: L. Idealis: cf. F. Ideal.