Choroid

n. choroidea, choroid coat, membrane of the eye containing blood vessels (Ophthalmology)

adj. pertaining to the chorion or structures which resemble the chorion (membrane which surrounds the fetus before birth)

The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye lying between the retina and the sclera, with a thickness about 0.5 mm. The choroid provides oxygen and nourishment to the outer layers of the retina [1].Along with the ciliary body and iris, the choroid forms the uveal tract. In humans and other primates, darkly colored melanin pigment in the choroid helps limit reflections within the eye that would potentially result in the perception of confusing images. Poor vision frequently results from lack of this pigmentation in human albinos. By contrast, the choroid of many other animals contains reflective materials that help to collect light in dim situations; this is one type of tapetum lucidum.
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Choroid /cho·roid/ 1. the middle, vascular coat of the eye, between the sclera and the retina.choroid´al 2. resembling the chorion. [more]Choroid - Community and Resources

Noun
1. a highly vascular membrane in the eye between the retina and the sclera
(synonym) choroid coat
(hypernym) membrane, tissue layer
(part-holonym) eye, oculus, optic

(n.)
The choroid coat of the eye. See Eye.
  

(a.)
resembling the chorion; as, the choroid plexuses of the ventricles of the brain, and the choroid coat of the eyeball.