Definition of tuatara
plural tu·a·tara or tu·a·taras
: 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 of tuatara
First Known Use: 1890
Learn More about tuatara
Britannica.com: Encyclopedia article about "tuatara"
Seen and Heard
What made you want to look up tuatara? Please tell us where you read or heard it (including the quote, if possible).