Having the structure and form of a crystal; composed of crystals
(In the compound eyes of many insects, crustacea, and other arthropods) a hard, refractive, conical body below the cornea of each ommatidium.
= crystalline lens.
(In various molluscs, especially bivalves) a long, transparent mucoid rod that projects from a sac into the stomach, where it rotates to aid mixing and gradually dissolves providing enzymes for digestion.
The transparent elastic structure behind the iris by which light is focused on to the retina of the eye
(In ancient and medieval astronomy) a transparent sphere of the heavens postulated to lie between the fixed stars and the primum mobile and to account for the precession of the equinox and other motions
(Of a solid) possessing crystalline character to some degree