(1):

(a.) Existing in idea or thought; conceptional; intellectual; mental; as, ideal knowledge.

(2):

(n.) A mental conception regarded as a standard of perfection; a model of excellence, beauty, etc.

(3):

(a.) Imaginary.

(4):

(a.) Teaching the doctrine of idealism; as, the ideal theory or philosophy.

(5):

(a.) Existing in fancy or imagination only; visionary; unreal.

(6):

(a.) Reaching an imaginary standard of excellence; fit for a model; faultless; as, ideal beauty.