small intestine

American  

noun

Anatomy.

small intestines plural

1. intestine.

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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

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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.

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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.

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Other Word Forms

Noun Inflected Forms

• small intestines
  plural

Etymology

Origin of small intestine

First recorded in 1760–70

Example Sentences

The effect was largely limited to the small intestine because that is where most dietary protein is absorbed.

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

The trial, led by Ghosh, began in November, and uses electrodes to detect activity of the small intestine.

From BBC • Mar. 11, 2026

Charles-Barclay said it took about a year for her small intestine to heal after making the necessary changes to her diet.

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