'Platonic' definitions:

Definition of 'Platonic'

adjective

Of or relating to or characteristic of Plato or his philosophy; "Platonic dialogues"

adjective

Free from physical desire; "platonic love"

From: GCIDE

Platonic \Pla*ton"ic\, Platonical \Pla*ton"ic*al\, a. [L. Platonicus, Gr. ?: cf. F. platonique.]
1. Of or pertaining to Plato, or his philosophy, school, or opinions. [1913 Webster]
2. Pure, passionless; nonsexual; philosophical. [1913 Webster]
Platonic bodies, the five regular geometrical solids; namely, the tetrahedron, hexahedron or cube, octahedron, dodecahedron, and icosahedron.
Platonic love, a pure, spiritual affection, subsisting between persons of opposite sex, unmixed with carnal desires, and regarding the mind only and its excellences; -- a species of love for which Plato was a warm advocate.
Platonic year (Astron.), a period of time determined by the revolution of the equinoxes, or the space of time in which the stars and constellations return to their former places in respect to the equinoxes; -- called also great year. This revolution, which is caused by the precession of the equinoxes, is accomplished in about 26,000 years. --Barlow. [1913 Webster]

From: GCIDE