I looked it up but.... say what????
<anatomy> Middle layer of the vertebrate eye, between retina and sclera.
Well vascularised and also pigmented to throw light back onto the retina (the tapetum is an irridescent layer in the choroid of some eyes). Not to be confused with the choroid plexus, a highly vascularised region of the roof of the ventricles of the vertebrate brain that secretes cerebrospinal fluid.