spleen

American  

[spleen] / splin /

noun

1. a highly vascular, glandular, ductless organ, situated in humans at the cardiac end of the stomach, serving chiefly in the formation of mature lymphocytes, in the destruction of worn-out red blood cells, and as a reservoir for blood.

2. Obsolete. this organ conceived of as the seat of spirit and courage or of such emotions as mirth, ill humor, melancholy, etc.

3. ill humor, peevish temper, or spite.

   Synonyms:

   anger, ire, wrath, acrimoniousness, rancor, petulance

4. Archaic. melancholy.

5. Obsolete. caprice.

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spleen British  

/ spliːn /

noun

1. a spongy highly vascular organ situated near the stomach in man. It forms lymphocytes, produces antibodies, aids in destroying worn-out red blood cells, and filters bacteria and foreign particles from the blood

2. the corresponding organ in other animals

3. spitefulness or ill humour; peevishness

   to vent one's spleen

4. archaic the organ in the human body considered to be the seat of the emotions

5. archaic another word for melancholy

6. obsolete whim; mood

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spleen Scientific  

/ splēn /

1. An organ in vertebrate animals that in humans is located on the left side of the abdomen near the stomach. The spleen is mainly composed of lymph nodes and blood vessels. It filters the blood, stores red blood cells (erythrocytes) and destroys old ones, and produces white blood cells (lymphocytes).

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spleen Cultural  

1. An organ in the lymphatic system, in the upper left part of the abdomen, that filters out harmful substances from the blood. The spleen also produces white blood cells, removes worn-out red blood cells from circulation, and maintains a reserve blood supply for the body.

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spleen Idioms  

1. see vent one's spleen.

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Other Word Forms

• spleenish adjective
• unspleenish adjective
• unspleenishly adverb

Etymology

Origin of spleen

1250–1300; Middle English < Latin splēn < Greek splḗn; akin to Sanskrit plīhan, Latin liēn spleen

Explanation

The spleen is an organ that's about the size of a fist, located on the left side, just below the ribcage. Don't let its small size fool you. This little organ is very important in helping the body fight infection. The spleen is responsible for removing old red blood cells and producing and storing a reserve of blood in case the body needs it. It's a little organ, measuring little more than four inches in length. The term "vent your spleen" is one you might see used. It means to vent your anger, as spleen is another word for bad temper or spite.

Example Sentences

The former pharmacy worker also lost her spleen, battled pneumonia and developed gallstones which she was told might require further surgery.

From BBC • Feb. 20, 2026

Kala-azar is spread by sandflies and is one of the most dangerous neglected tropical diseases, with a fatality rate of 95 percent if untreated, causing fever, weight loss, and enlargement of the spleen and liver.

From Barron's • Feb. 8, 2026

Agnes cares for her second daughter so devoutly that her worry can’t help but portend tragedy, and Zhao and O’Farrell’s foreshadowing is as subtle as a sword to the spleen.

From Salon • Nov. 30, 2025

In mouse models, the new therapy nearly eliminated leukemia cells in the blood and spleen while significantly extending survival time.

From Science Daily • Nov. 5, 2025

It turned out that at the age of thirty-one, Moore had hairy-cell leukemia, a rare and deadly cancer that filled his spleen with malignant blood cells until it bulged like an overfilled inner tube.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot

Related Words

• ill humor
• ill temper
• peevishness