spleen

American  

[spleen] / splin /

noun

spleens plural

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.

---

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

---

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).

---

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.

---

spleen Idioms  

1. see vent one's spleen.

---

Other Word Forms

Derived Forms

• spleenish
  adjective
• unspleenish
  adjective
• unspleenishly
  adverb

Inflected Forms

Nouns

• spleens
  plural

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

See Examples For:

spleen spleens

And amid all the sturm und drang, each character projects onto the other a pent-up spleen of parent-child neuroses and unmet expectations.

From The Wall Street Journal ● May 28, 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

Further CT and MRI scans revealed an enlarged spleen and, in September 2025, she was diagnosed with myelofibrosis.

From BBC ● Jan. 26, 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

We four children stayed out of their way and continued to vent our group spleen amongst ourselves, muttering about the unfairness of it all.

From "The Evolution of Calpurnia Tate" by Jacqueline Kelly

They were looking at “scurfy” mice; males are unexpectedly born with flaky skin and enlarged spleens and only live for a few weeks, because their organs are attacked by their own immune cells.

From The Wall Street Journal ● Oct. 6, 2025

People without spleens are more susceptible to severe bacterial infections.

From Los Angeles Times ● Dec. 21, 2022

When the researchers transfused red blood cells into the animals, macrophages in their spleens gobbled cells that had been exposed to CpG-laden DNA, but ate fewer red blood cells that hadn’t encountered the DNA.

From Science Magazine ● Oct. 19, 2021

Yet this bedrock right to vent our spleens against officials is now being challenged.

From Salon ● Mar. 26, 2021

They appeared to have died of heat stress, brought on, he suspected, by the problems with the heating system in the building—but their spleens were weirdly enlarged.

From "The Hot Zone" by Richard Preston

Related Words

• ill humor
• ill temper
• peevishness