small intestine

American  

noun

Anatomy.

• small intestines
  plural

1. intestine.

---

small intestine British  

noun

1. the longest part of the alimentary canal, consisting of the duodenum, jejunum, and ileum, in which digestion is completed Compare large intestine

---

small intestine Scientific  

1. The long, narrow, coiled section of the intestine that extends from the stomach to the beginning of the large intestine. Nutrients from food are absorbed into the bloodstream from the small intestine. In mammals, it is made up of the duodenum, jejunum, and ileum.

---

small intestine Cultural  

1. The upper portion of the intestines, extending from the stomach to the large intestine, where the digestion of food takes place. The small intestine is about twenty feet long in adults.

---

Other Word Forms

Noun Inflected Forms

• small intestines
  plural

Etymology

Origin of small intestine

First recorded in 1760–70

Example Sentences

See Examples For:

small intestine

The researchers found that these activated T cells gather in the lining of the small intestine, placing them in an ideal position to respond quickly when damage occurs.

From Science Daily ● May 21, 2026

In a new study, scientists found that cysteine can activate an immune response that boosts intestinal stem cells and helps regenerate tissue in the small intestine.

From Science Daily ● May 21, 2026

Their approach uses a cyclic peptide that can pass through the small intestine, known as the DNP peptide.

From Science Daily ● Mar. 24, 2026

But that all changed in 2024 when she received a "game-changing diagnosis" of coeliac disease, an autoimmune condition whereby consuming gluten causes the body's immune system to attack internal organs, including the small intestine.

From BBC ● Dec. 10, 2025

The tumor in the small intestine is harder to measure.

From "All the Light We Cannot See" by Anthony Doerr