coccyx

noun

coc·​cyx ˈkäk-siks 

plural coccyges ˈkäk-sə-ˌjēz  also coccyxes ˈkäk-sik-səz 

: a small bone that articulates with the sacrum and that usually consists of four fused vertebrae which form the terminus of the spinal column in humans and tailless apes

Examples of coccyx in a Sentence

Recent Examples on the Web

My generation's ability to remember phone numbers is a bit of a coccyx – the vestigial remainder of a structure no longer required. —New Atlas, 17 Feb. 2025

Excess weight can affect any area of the back, including the cervical spine (neck), thoracic spine (upper and mid-back), lumbar spine (lower back), and the sacrum and coccyx (posterior pelvic wall and tailbone). —Lana Barhum, Verywell Health, 1 Aug. 2024

Its contoured shape is designed to evenly distribute pressure and help relieve coccyx and tailbone pain. —Good Housekeeping, 9 Aug. 2023

The remnant that remains is the tailbone, also called the coccyx. —Allison Futterman, Discover Magazine, 13 Apr. 2023

Like the ComfiLife, this mat’s high-density polyurethane foam core provides excellent support, and its manufacturer advertises that the mat can help reduce fatigue and spinal and coccyx compression while promoting active standing. —Chuong Nguyen, Ars Technica, 9 Mar. 2023

Your vertebrae are divided into sections: your cervical spine (hi, neck bones), your thoracic spine (the upper part of your back), your lumbar spine (lower back), your sacrum (this joins with your pelvis), and your coccyx (a funny way to say tailbone). —Demetria Wambia, SELF, 17 Feb. 2022

By birth, the tail has disappeared and the vertebrae fused to form the coccyx or tailbone. —Scott Lafee, San Diego Union-Tribune, 25 Oct. 2022

These include such otherwise inexplicable ones as the pelvis and leg bones of whales and snakes, the wings of flightless birds, and the human coccyx (tailbone). —David P. Barash, WSJ, 29 Dec. 2020

Word History

Etymology

New Latin, from Greek kokkyx cuckoo, coccyx; from its resemblance to a cuckoo's beak

First Known Use

1615, in the meaning defined above

Kids Definition

coccyx

noun

coc·​cyx ˈkäk-siks 

plural coccyges ˈkäk-sə-ˌjēz  also coccyxes ˈkäk-sik-səz 

: the bone at the end of the spinal column that is composed of four vertebrae combined into one bone

Medical Definition

coccyx

noun

coc·​cyx ˈkäk-siks 

plural coccyges ˈkäk-sə-ˌjēz  also coccyxes ˈkäk-sik-səz 

: a small bone that articulates with the sacrum and that usually consists of four fused vertebrae which form the terminus of the spinal column