thagomizer

noun

Etymology: Coined by cartoonist Gary Larson in 1982. His comic strip (image on the right) shows a caveman giving a lecture illustrating this part of a dinosaur, with the caption "Now this end is called the thagomizer... after the late Thag Simmons". See -ize, -er.

1. An arrangement of spikes found on the tails of various stegosaurs.

   “Like the thagomizer of the stegosaur, the ankylosaurid tail club was probably used to smash into attackers.”

   “An Allosaurus backbone had a hole in which a Stegosaurus thagomizer fitted perfectly. Over the years, many of the fossil thagomizers that have been dug up have had broken tips.”