chickenpox

noun

chick·​en·​pox ˈchi-kᵊn-ˌpäks How to pronounce chickenpox (audio)
variants or less commonly chicken pox
: an acute contagious disease especially of children marked by low-grade fever and formation of vesicles (see vesicle sense 1b) and caused by a herpesvirus (Varicellovirus humanalpha3) compare shingles

Word History

First Known Use

1691, in the meaning defined above

Time Traveler
The first known use of chickenpox was in 1691

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Cite this Entry

“Chickenpox.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/chickenpox. Accessed 9 Nov. 2025.

Kids Definition

chicken pox

noun
: a contagious virus disease especially of children marked by low fever and a rash or small watery blisters

Medical Definition

chickenpox

noun
chick·​en·​pox ˈchik-ən-ˌpäks How to pronounce chickenpox (audio)
variants also chicken pox
: an acute contagious disease especially of children that is marked by low-grade fever and formation of vesicles (see vesicle sense 2) and that is caused by a herpesvirus (Varicellovirus humanalpha3)

called also varicella

see shingles
Last Updated: - Definition revised
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