nic·​ti·​tate ˈnik-tə-ˌtāt How to pronounce nictitate (audio)
nictitated; nictitating

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Nictitate and the Zoo

Nictitate didn't just happen in the blink of an eye; it developed over time as an alteration of the older verb nictate, which also means "to wink." Both verbs trace to the Latin word for winking, nictare. The addition of the extra syllable was apparently influenced by Latin verbs ending in -itare, such as palpitare and agitare (which gave us palpitate and agitate, respectively). Today, nictitate has a special use in the animal world. Since the early 18th century, scientists have used nictitating membrane to describe the so-called "third eyelid": the thin, usually transparent membrane in the eyes of birds, fishes, and other vertebrates that helps keep the eyeball moist and clean.

Word History


alteration of nictate to wink, from Latin nictatus, past participle of nictare — more at connive

First Known Use

1713, in the meaning defined above

Time Traveler
The first known use of nictitate was in 1713


Dictionary Entries Near nictitate

Cite this Entry

“Nictitate.” Dictionary, Merriam-Webster, Accessed 5 Dec. 2022.

Medical Definition


intransitive verb

nic·​ti·​tate ˈnik-tə-ˌtāt How to pronounce nictitate (audio)
nictitated; nictitating
: wink
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