triceratops
Rare term for the dinosaur Triceratops. The more common name is トリケラトプス.
I saw a Triceratops fossil in the picture book.
From 三角 (さんかく, 'triangle') + 竜 (りゅう, 'dragon'), referring to the three horns. A Japanese coinage for Triceratops, now largely replaced by the loanword トリケラトプス.