mas·​ti·​tis ma-ˈstī-təs How to pronounce mastitis (audio)
plural mastitides ma-ˈsti-tə-ˌdēz How to pronounce mastitis (audio)
: inflammation of the breast or udder usually caused by infection
mastitic adjective

Example Sentences

Recent Examples on the Web Another client, Michelle Galanek, developed mastitis, a breast infection, followed by an abscess shortly after her second child was born. Frances Stead Sellers, Anchorage Daily News, 19 May 2022 Currin’s females, her breasts are gargantuan, just rounded mastitis masses. Jerry Saltz, Vulture, 12 Nov. 2021 What about babies’ ear infections or breastfeeding moms’ mastitis? Theresa Sullivan Barger, Discover Magazine, 23 Nov. 2021 While many only hear about TSS when talking about tampons, it can actually be caused by other non-menstrual related circumstances like surgical wound infections, mastitis, sinusitis, burns or respiratory infections following influenza. Emma Seymour, Good Housekeeping, 31 Oct. 2022 Having clogged ducts and mastitis, an inflammation and infection of the breast, is pretty common among breastfeeding moms, according to the Mayo Clinic Health System. Shafiq Najib,, 27 June 2022 Failure to express milk regularly can also lead to a breast infection called mastitis. Kim Elsesser, Forbes, 12 Aug. 2022 The Everything Bra, which was designed for all-day comfort and helps to potentially lower the risk of mastitis and clogged ducts. Danielle Directo-meston, The Hollywood Reporter, 18 Apr. 2022 In this week's episode of PEOPLE's podcast Me Becoming Mom, the actress recalls her experience with mastitis and how wearing an underwire bra may have caused the inflammation. Georgia Slater,, 3 Feb. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mastitis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


Greek mastós "breast, nipple" (probably from a pre-Greek substratal language) + -itis, probably after French mastite

First Known Use

circa 1842, in the meaning defined above

Time Traveler
The first known use of mastitis was circa 1842

Dictionary Entries Near mastitis

Cite this Entry

“Mastitis.” Dictionary, Merriam-Webster, Accessed 21 Mar. 2023.

Medical Definition


mas·​ti·​tis ma-ˈstīt-əs How to pronounce mastitis (audio)
plural mastitides -ˈtit-ə-ˌdēz How to pronounce mastitis (audio)
: inflammation of the mammary gland or udder usually caused by infection

called also mammitis

see blue bag, bovine mastitis, garget, summer mastitis

More from Merriam-Webster on mastitis

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