n. [ NL., from L. rete a net. Cf. Reticule. ] (Anat.) The delicate membrane by which the back part of the globe of the eye is lined, and in which the fibers of the optic nerve terminate. See Eye. [ 1913 Webster ]

☞ The fibers of the optic nerve and the retinal blood vessels spread out upon the front surface of the retina, while the sensory layer (called Jacob's membrane), containing the rods and cones, is on the back side, next the choroid coat. [ 1913 Webster ]

‖n.; pl. Retinacula [ L., a holdfast, a band. See Retain. ] 1. (Anat.) (a) A connecting band; a fraenum; as, the retinacula of the ileocaecal and ileocolic valves. (b) One of the annular ligaments which hold the tendons close to the bones at the larger joints, as at the wrist and ankle. [ 1913 Webster ]

2. (Zool.) One of the retractor muscles of the proboscis of certain worms. [ 1913 Webster ]

3. (Bot.) A small gland or process to which bodies are attached; as, the glandular retinacula to which the pollinia of orchids are attached, or the hooks which support the seeds in many acanthaceous plants. [ 1913 Webster ]

a. (Anat.) Of or pertaining to the retina. [ 1913 Webster ]

Retinal purple (Physiol. Chem.), the visual purple. [ 1913 Webster ]

n. (Chem.) A retinoid compound (C20H28O), closely related to vitamin A, which is a component of the visual pigments in the eye. It is also called retinaldehyde and vitamin A aldehyde. [ PJC ]

n. [ Gr. &unr_;&unr_;&unr_;&unr_; resin + -lite. ] (Min.) A translucent variety of serpentine, of a honey yellow or greenish yellow color, having a waxy resinlike luster. [ 1913 Webster ]

{ ‖ } n. [ Gr. &unr_;&unr_;&unr_;&unr_; resin + &unr_;&unr_;&unr_;&unr_;&unr_; asphalt. ] (Min.) Retinite. [ 1913 Webster ]