Definition of "coccyx" []

• A small triangular bone at the base of the spinal column in humans and tailless apes, consisting of several fused rudimentary vertebrae. Also called tailbone. (noun)

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.

• "The sore coccyx is a result of sitting down for too long, in the same position, in a half decent chair!"
• "Also note how much longer and more solid the sacrum (with its attached bone, called the coccyx [2]) is in the male pelvis."
• "—In the middle line of the posterior part of the perineum and about 4 cm. in front of the tip of the coccyx is the anal orifice."