third eyelid
1
8.9
- noun
- Specialized
:
tercera membrana
- A new monoclonal antibody test can detect telltale prions in lymphoid tissue taken from a sheep's third eyelid.
- nictitating third eyelid
- third eyelid membrane
Examples
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Prions collect on this third eyelid, explains O'Rourke.
Academic text (2002) -
There, O'Rourke had also helped pioneer the development of a so-called third-eyelid test to detect scrapie's main causative agent: a malformed protein called a prion.
Academic text (2002) -
He bases this on their skin color and that third eyelid they have.
Fiction book (1999) -
Later, O'Rourke had a real breakthrough when she discovered that prions collect in pockets of lymphoid tissue in a sheep's nictitating membrane, or third eyelid.
Academic text (2004) -
But with the eyelid test, all that's needed is a small sample of lymph tissue snipped from a special membrane covering the sheep's eye, called the third eyelid.
Academic text (2002) -
Many birds have a third eyelid that protects their eyes while they fly.
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The third eyelid in reptiles helps keep their eyes moist and free from debris.
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When the crocodile swims, it uses its third eyelid to see underwater without losing visibility.
Synonyms
1
9.9
A thin transparent third eyelid that protects and keeps the eye wet
A thin protective third eyelid in the inner corner of an eye
Surface Forms
Morphology
The meaning 'an additional eyelid' is directly and compositionally derivable from 'third' (an extra/number three) + 'eyelid' (the protective skin fold over the eye). Even if learners do not know the anatomical term for the membrane, a B1 learner who knows both constituents can infer it is another eyelid; this composition is cross-linguistically common and follows straightforward noun modification patterns.
Etymology
Third eyelid names a thin, clear flap, a small extra eyelid, that some animals can pull across their eye to clean and protect it. So the term means 'an extra protective eyelid' that keeps the eye moist and safe.