root canal
From Longman Dictionary of Contemporary Englishroot canalˈroot caˌnal noun [countable] the space inside the root of a tooth root canal treatment (=treatment in which a dentist removes a diseased area in the root of a tooth)Examples from the Corpusroot canal• I had a throbbing abscess under a large section of bridgework and root canal work was the next day's projected treat.• He got out of bed on Wednesday morning, feeling the same dread he might feel over an impending root canal.