sphincter

American  

[sfingk-ter] / ˈsfɪŋk tər /

noun

Anatomy.

1. a circular band of voluntary or involuntary muscle that encircles an orifice of the body or one of its hollow organs.

---

sphincter British  

/ ˈsfɪŋktə /

noun

1. anatomy a ring of muscle surrounding the opening of a hollow organ or body and contracting to close it

---

sphincter Scientific  

/ sfĭngk′tər /

1. A ring-shaped muscle that encircles an opening or passage in the body. The opening and closing of the anus is controlled by contraction and relaxation of a sphincter, as is the opening that leads to the stomach from the esophagus.

---

Other Word Forms

• sphincteral
  adjective
• sphincterate
  adjective
• sphincterial
  adjective
• sphincteric
  adjective

Etymology

Origin of sphincter

1570–80; < Late Latin < Greek sphinktḗr, equivalent to sphing-, base of sphíngein to hold tight + -tēr suffix denoting agent

Example Sentences

It was only after the birth of her second child, three years later, that she was referred to a colorectal surgeon who discovered an anal sphincter tear.

From BBC • May 13, 2026

The detrusor muscle of the bladder wall relaxes to allow the bladder to fill and empty, while the external sphincter opens when it's appropriate to allow urine to flow out, but otherwise keeps tightly shut.

From Science Daily • Dec. 3, 2024

Reduced pressure on the urinary sphincter is one of the many sensations dulled by living in microgravity, along with smell, taste and sight.

From Salon • Nov. 22, 2024

This can make your stomach produce more acid, and it can also relax the sphincter muscle between your stomach and esophagus, allowing stomach acid to back up into your esophagus.

From Seattle Times • Mar. 4, 2024

Ms. Sorenstein sent him on his way, and then Colin went into the bathroom and, staring in the mirror, plucked the eyelash from his eye, where the pupillary sphincter is located.

From "An Abundance of Katherines" by John Green