dì sān yǎn jiǎn
(zoology) nictitating membrane
第
dì
(prefix indicating ordinal number, as in 第六[di4 liu4] "sixth")
三
sān
three
眼
yǎn
eye (CL:隻|只[zhi1],雙|双[shuang1])
睑
jiǎn
eyelid
