“Choroid” is defined as follows, by Merriam-Webster: “A vascular membrane containing large branched pigmented cells that lies between the retina and the sclera of the vertebrate eye.”

Machine Briefs:
Option #1: choroid= KOR/ROID
Option #2: choroid= KHOR/ROID
[SIDEBAR: I like to use the brief KHOR/ROID because it doesn’t conflict with “corps reside” like KOR/ROID does.]