American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "tetragon" in a sentence
"I'm sure she's pulling her gray hair out at missing her chance to baffle both kids and parents with "tetragon", but hey, she could always write a sequel!)"
"“A tetragon that acts like an octahedron,” the Doctor said."
"Be there or be an equilateral tetragon with four eight-point angles."