Literally meaning: “inflammation of peritoneum”
Origin: Anc Greek
περί-/peri- (=combining form meaning “around”)
+τόνος/tonos(=stretching) > τανύω/taneo(=strain)
+-ίτις/-tis(=(=suffix which is used with the feminine noun η νόσος/ e nosos/=disease, denoting “inflammation of”).
Peritonitis is the inflammation of the peritoneum (the thin membrane that lines part of the abdominal and pelvic cavitiy, and covers most abdominal viscera and organs).