Definition of pineal eye in US English:

pineal eye


  • (in some reptiles and lower vertebrates) an eye-like structure on the top of the head, covered by almost transparent skin and derived from or linked to the pineal.

    • ‘A pineal eye was present, although not usually open to the surface.’
    • ‘Researchers at the University of Maryland have found that larval blind cavefish retain a functioning pineal eye that is capable of detecting light.’