optic

Of or relating to the eye or vision.

Of or relating to the science of optics or optical equipment.

An eye.

Any of the lenses, prisms, or mirrors of an optical instrument.

Relating or pertaining to vision or sight; visual; subservient to the faculty or function of seeing.

Of or pertaining to the eye as the organ of vision; ocular; ophthalmic.

Relating to the science of optics.

The angle which the visual axes of the eyes make with one another as they tend to meet at some distance before the eyes.

The angle between the optic axes in a biaxial crystal.

The line in a doubly refracting crystal in the direction of which no double refraction occurs. Crystals belonging to the tetragonal and hexagonal systems have a single optic axis, coincident with their vertical crystallographical axis: hence they are said to be uniaxial. Crystals belonging to the orthorhombic, monoclinic, and triclinic systems have two optic axes, and hence are biaxial.