peritoneum

noun

peri·​to·​ne·​um ˌper-ə-tə-ˈnē-əm 

plural peritoneums ˌper-ə-tə-ˈnē-əmz  or peritonea ˌper-ə-tə-ˈnē-ə 

: the smooth transparent serous membrane that lines the cavity of the abdomen of a mammal and is folded inward over the abdominal and pelvic viscera

peritoneal

ˌper-ə-tə-ˈnē-əl 

adjective

peritoneally

ˌper-ə-tə-ˈnē-ə-lē 

adverb

Examples of peritoneum in a Sentence

Recent Examples on the Web

This area contains the peritoneum, a thin layer of tissue that lines the abdominal wall and covers the organs. —Julie Scott, Msn, Anp-Bc, People.com, 28 Feb. 2025

Then the cancer came back in the peritoneum, the lining of his abdomen. —Wendy Grossman Kantor, People.com, 27 Nov. 2024

Abdominal Bloating, Pain, or Tenderness Abdominal bloating, pain, or tenderness can be a sign of metastatic breast cancer that has spread to the liver or the lining of the abdominal cavity, called the peritoneum. —Julie Scott, Msn, People.com, 2 Oct. 2024

In stage 4c, rectal cancer has spread to the abdominal wall lining (peritoneum). —Corey Whelan, Verywell Health, 15 Aug. 2024

Somatic pain: This pain usually comes from irritation of the peritoneum, the protective lining of the abdominal cavity. —Lindsay Curtis, Health, 10 July 2024

Normally this causes fever and abdominal pain that is initially felt in the region around the belly button but then moves to the right lower quadrant as the infection and inflammation spread to the highly sensitive lining of the abdominal cavity known as the peritoneum. —Lisa Sanders, M.d., New York Times, 10 Jan. 2024

Peritoneal dialysis uses the peritoneum, the lining of the abdomen, which contains the organs, to mimic a kidney by using large amounts of fluid inside the peritoneum to absorb wastes without needing to remove the blood from the body. —Dr. Keith Roach, oregonlive, 9 Feb. 2022

What’s under it is the same as what’s under the skin of the rest of your abdomen: your abdominal muscles, to which the navel is attached by a short umbilical stalk, and the peritoneum, the membrane that lines the abdominal cavity. —Sarah Leupen, The Conversation, 5 Apr. 2023

Word History

Etymology

Middle English, from Late Latin, from Greek peritonaion, neuter of peritonaios stretched around, from peri- + teinein to stretch — more at thin

First Known Use

15th century, in the meaning defined above

Rhymes for peritoneum

• endothelium
• periosteum
• athenaeum
• coliseum
• colosseum
• mausoleum
• mycelium
• corneum
• hordeum
• luteum
• lyceum
• museum

Kids Definition

peritoneum

noun

peri·​to·​ne·​um ˌper-ət-ᵊn-ˈē-əm 

plural peritoneums or peritonea

-ˈnē-ə

: the smooth transparent membrane that lines the cavity of the abdomen and encloses the abdominal and pelvic organs

Medical Definition

peritoneum

noun

peri·​to·​ne·​um

variants or chiefly British peritonaeum

ˌper-ət-ᵊn-ˈē-əm 

plural peritoneums or chiefly British peritonaeums -ˈē-əmz  or peritonea or chiefly British peritonaea -ˈē-ə 

: the smooth transparent serous membrane that lines the cavity of the abdomen of a mammal, is folded inward over the abdominal and pelvic viscera, and consists of an outer layer closely adherent to the walls of the abdomen and an inner layer that folds to invest the viscera see parietal peritoneum, visceral peritoneum compare mesentery sense 1