Tapetum
Pronunciation : Ta*pe"tum
Part of Speech : n.
Etymology : [NL., from L. tapete a carpet, a tapestry.] (Anat.)
Definition : Defn: An area in the pigmented layer of the choroid coat of the eye in many animals, which has an iridescent or metallic luster and helps to make the eye visible in the dark. Sometimes applied to the whole layer of pigmented epithelium of the choroid.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder