nictitating membrane

English Thesaurus

1. a protective fold of skin in the eyes of reptiles and birds and some mammals (noun.body)

hypernym	:	protective fold,
definition	:	a flap of tissue that protects what it covers (noun.body)

hyponym	:	haw,
definition	:	the nictitating membrane of a horse (noun.body)

part meronym	:	eye, oculus, optic,
definition	:	the organ of sight (noun.body)