cyst

1 of 3

noun

1
: a closed sac having a distinct membrane and developing abnormally in a cavity or structure of the body
2
: a body resembling a cyst: such as
a
: a resting spore of many algae
b
: the air bladder of certain algae or aquatic plants (such as rockweed)
c
: a capsule formed about a minute organism going into a resting or spore stage
also : this capsule with its contents
d
: a resistant cover about a parasite produced by the parasite or the host

cyst-

2 of 3

combining form

variants or cysti- or cysto-
: bladder
cystitis
: sac
cystocarp

-cyst

3 of 3

noun combining form

: bladder : sac
blastocyst

Examples of cyst in a Sentence

Recent Examples on the Web
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Noun
Bob underwent experimental cancer treatment shortly after retiring, Alex had brain surgery in 2022 to address a cyst that had caused brain swelling. Barbara Bry, San Diego Union-Tribune, 15 June 2025 Remington had a facial cyst at just 18 months old and specialist care helped him into remission. Alice Gibbs, MSNBC Newsweek, 12 June 2025 Hough detailed her highs and lows on the show, including having a cyst burst on live television. Dayna Haffenden, People.com, 3 June 2025 In 2017, my colleagues and I found that Toxoplasma can also form cysts in mouse prostates. Bill Sullivan, The Conversation, 28 May 2025 See All Example Sentences for cyst

Word History

Etymology

Noun

New Latin cystis, from Greek kystis bladder, pouch; akin to Sanskrit śvasiti he blows, snorts — more at wheeze

Combining form

French, from Greek kyst-, kysto-, from kystis

Noun combining form

New Latin -cystis, from Greek kystis

First Known Use

Noun

circa 1723, in the meaning defined at sense 1

Time Traveler
The first known use of cyst was circa 1723

Browse Nearby Words

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Cite this Entry

“Cyst.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cyst. Accessed 1 Jul. 2025.

Kids Definition

cyst

noun
1
: a closed pouch or sac of fluid or solid material that develops in the body in some diseased conditions
2
: a covering resembling a cyst or a body (as a spore) with such a covering
cystic
ˈsis-tik
adjective

Medical Definition

cyst

noun
1
: a closed sac having a distinct membrane and developing abnormally in a body cavity or structure
2
: a body resembling a cyst: as
a
: a capsule formed about a minute organism going into a resting or spore stage
also : this capsule with its contents
b
: a resistant cover about a parasite produced by the parasite or the host compare hydatid sense 2a

More from Merriam-Webster on cyst

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