nematocyst

American  

[nem-uh-tuh-sist, ni-mat-uh-] / ˈnɛm ə təˌsɪst, nɪˈmæt ə- /

noun

Zoology.

1. an organ in coelenterates consisting of a minute capsule containing an ejectable thread that causes a sting.

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nematocyst British  

/ nɪˈmætə-, ˈnɛmətəˌsɪst /

noun

1. a structure in coelenterates, such as jellyfish, consisting of a capsule containing a hollow coiled thread that can be everted to sting or paralyse prey and enemies

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nematocyst Scientific  

/ nĕm′ə-tə-sĭst′,nĭ-măt′ə-sĭst′ /

1. One of the minute capsules in the tentacles of cnidarians, such as jellyfish, hydras, or sea anemones, used for stinging. The capsule is produced by a special cell (called a cnidoblast) and contains a tightly coiled barbed thread that quickly shoots forth if the capsule's lid is disturbed. The thread often contains poison.

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Other Word Forms

• nematocystic adjective

Etymology

Origin of nematocyst

First recorded in 1870–75; nemato- + -cyst

Example Sentences

When the nematocyst fires, the shaft is ejected first and turns right-side out.

From Scientific American • Sep. 14, 2022

Using super-resolution fluorescence and electron microscopes, the researchers observed a detailed sequence of events involving a stiff shaft and a flexible, whiplike filament that starts out coiled around it within the nematocyst.

From Scientific American • Sep. 14, 2022

Next comes the nematocyst, a larger dart, with a long tube attached.

From New York Times • Mar. 31, 2017

Inside the nematocyst, a thread is coiled around an inverted barb.

From Textbooks • Jan. 1, 2015

The polar-capsule is an organella which recalls the nematocyst of a Hydrozoan, containing a spirally-coiled filament, often of great length, which is shot out on the application of a suitable stimulus.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" by Various