Definition of tuatara
: a large spiny quadrupedal reptile (Sphenodon punctatum) of islands off the coast of New Zealand that has a vestigial third eye in the middle of the forehead representing the pineal gland and that is the only surviving rhynchocephalian
Origin and Etymology of tuatara
First Known Use: 1890
Learn More about tuatara
Britannica.com: Encyclopedia article about tuatara
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