canker sore
noun
: a painful shallow ulcer of the mouth that has a grayish-white base surrounded by a reddish inflamed area and is of uncertain cause but is not due to the virus causing herpes simplex compare cold sore
Example Sentences
Recent Examples on the Web People can confuse a cold sore for a canker sore, an angry noncontagious lesion that isn’t linked with herpes, or an exceptionally painful pimple, at least in the beginning before the blister opens up. 
Zahra Barnes, SELF, 3 Jan. 2022 Keith Negley The day after her school closed its doors for social distancing, a canker sore developed in my daughter’s mouth. Danielle Braff, New York Times, 16 Apr. 2020 The headache, canker sore, and chest tightness were the most prevalent symptoms during this time period. Kara Ladd, Health.com, 1 Apr. 2020 In fact, there seems to be no ailment Wim Hof’s method—the Wim Hof Method—does not claim to at least partially address: stress, arthritis, cancer, migraines, canker sores, fibromyalgia, Crohn’s Disease, ALS, MS, and HIV. Rachel Sugar, Bon Appétit, 28 Oct. 2019 And the lack of those nutrients develops canker sores. The New Yorker, 10 July 2019 The products--sold under brand names like Orajel and Chloraseptic, as well as store brands and generics--are often used for relief from sore throats, canker sores and other oral irritations, according to the FDA. Laura Mcknight, NOLA.com, 23 May 2018 Most canker sores resolve on their own within one to two weeks. Roni Caryn Rabin, New York Times, 16 Mar. 2018 Now, for the burning question: Is alum a miracle treatment for canker sores? Zahra Barnes, SELF, 12 Dec. 2017 See More
Zahra Barnes, SELF, 3 Jan. 2022 Keith Negley The day after her school closed its doors for social distancing, a canker sore developed in my daughter’s mouth. Danielle Braff, New York Times, 16 Apr. 2020 The headache, canker sore, and chest tightness were the most prevalent symptoms during this time period. Kara Ladd, Health.com, 1 Apr. 2020 In fact, there seems to be no ailment Wim Hof’s method—the Wim Hof Method—does not claim to at least partially address: stress, arthritis, cancer, migraines, canker sores, fibromyalgia, Crohn’s Disease, ALS, MS, and HIV. Rachel Sugar, Bon Appétit, 28 Oct. 2019 And the lack of those nutrients develops canker sores. The New Yorker, 10 July 2019 The products--sold under brand names like Orajel and Chloraseptic, as well as store brands and generics--are often used for relief from sore throats, canker sores and other oral irritations, according to the FDA. Laura Mcknight, NOLA.com, 23 May 2018 Most canker sores resolve on their own within one to two weeks. Roni Caryn Rabin, New York Times, 16 Mar. 2018 Now, for the burning question: Is alum a miracle treatment for canker sores? Zahra Barnes, SELF, 12 Dec. 2017 See More Word History
First Known Use
circa 1596, in the meaning defined above
Kids Definition
canker sore
noun
can·ker sore
ˈkaŋ-kər-
: a small painful sore of the mouth
Medical Definition
canker sore
noun
: a small painful ulcer especially of the mouth
especially : a painful shallow ulceration of the oral mucous membranes that has a grayish-white base surrounded by a reddish inflamed area and is characteristic of aphthous stomatitis compare cold sore