cyst
Medical term for a fluid-filled sac in the body. Often used in compound words like 卵巣嚢腫 (ovarian cyst).
See also: 嚢胞
An ultrasound found a cyst on the ovary.
A radicular cyst is a cyst that forms at the root of a tooth.
Mixed kana-kanji spelling; 嚢 is a non-jōyō kanji, so this form is sometimes used for readability.
From 嚢 (sac) + 腫 (swelling/tumor). The exact historical derivation is uncertain; the spelling is conventionally associated with the medical meaning.