coccyx

[ kok-siks ]

noun

, plural coc·cy·ges [kok-, sahy, -jeez, kok, -si-jeez].

1. a small triangular bone forming the lower extremity of the spinal column in humans, consisting of four ankylosed rudimentary vertebrae.
2. a corresponding part in certain animals.

coccyx

/ kɒkˈsɪdʒɪəl; ˈkɒksɪks /

noun

1. a small triangular bone at the end of the spinal column in man and some apes, representing a vestigial tail

coccyx

/ kŏk′sĭks /

, Plural coccyges kŏk-sī′jēz,kŏk′sĭ-jēz′

1. A small triangular bone at the base of the spine in humans and apes. It is composed of several fused vertebrae.
2. Also called tailbone

Derived Forms

• coccygeal, adjective

Other Words From

• coc·cyg·e·al [kok-, sij, -ee-, uh, l, -, sij, -, uh, l], adjective
• inter·coc·cyge·al adjective
• precoc·cyge·al adjective

Word History and Origins

Origin of coccyx¹

1605–15; < New Latin < Greek kókkyx cuckoo, from its resemblance to a cuckoo's beak

Word History and Origins

Origin of coccyx¹

C17: from New Latin, from Greek kokkux cuckoo, of imitative origin; from the likeness of the bone to a cuckoo's beak

Example Sentences

Following this evolutionary split, the group of apes that includes present-day humans evolved the formation of fewer tail vertebrae, giving rise to the coccyx, or tailbone.

From Science Daily

Davidson had revealed that Kelly had bruised his coccyx after the two fell off the stage at "Saturday Night Live."

From Fox News

He noted that while humans and apes lack a visible tail, they share a tiny set of vertebrae that extend beyond the pelvis — a structure known as the coccyx.

From New York Times

The coccyx cushion in his cart suggests he may have suffered a fall.

From The Verge

If you wanted to slip and slide around in a circle and be in danger of banging your coccyx, you could go home and mop, which you have never before desired to do.

From Washington Post