nematocyst
C2 / Very Low Frequency (Scientific/Technical)Technical/Scientific (Biology, Marine Biology, Zoology)
Definition
Meaning
A stinging cell, capsule, or organ found in certain animals (mainly coelenterates like jellyfish), used for defense and capturing prey.
The specialized microscopic structure containing a coiled, barbed thread that can be ejected to deliver a toxin. Can also refer, by extension, to the entire stinging apparatus of a cnidarian.
Linguistics
Semantic Notes
Primarily a count noun. It is a subset of the broader term 'cnida'. The term is highly specific to the phylum Cnidaria (jellyfish, corals, sea anemones).
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Both dialects use the term identically within technical contexts.
Connotations
None beyond its precise scientific meaning.
Frequency
Equally rare and specialized in both dialects, used exclusively in scientific discourse.
Vocabulary
Collocations
Grammar
Valency Patterns
The [JELLYFISH TENTACLE] is armed with nematocysts.The [CELL] discharged its nematocyst upon contact.Vocabulary
Synonyms
Strong
Neutral
Weak
Usage
Context Usage
Business
Not used.
Academic
Used in marine biology, zoology, and toxicology papers. E.g., 'The study characterized the nematocyst venom proteome.'
Everyday
Virtually never used. If mentioned, it's in the context of a jellyfish sting explanation.
Technical
The primary context. Used in species descriptions, anatomical studies, and research on venom delivery mechanisms.
Examples
By Part of Speech
adjective
British English
- The nematocyst density was measured.
- Nematocyst morphology varies.
American English
- The nematocyst density was measured.
- Nematocyst morphology varies.
Examples
By CEFR Level
- Jellyfish have stinging cells called nematocysts on their tentacles.
- Upon touching the tentacle, the pressure triggers the nematocyst to fire its barbed thread.
- The nematocyst's discharge is one of the fastest biological processes, involving extreme osmotic pressure and the eversion of the coiled tubule.
Learning
Memory Aids
Mnemonic
Think: NEMAto like 'nemesis' (an enemy) + CYST (a sac). It's a 'nemesis-sac' that stings.
Conceptual Metaphor
A HARPOON GUN or a SPRING-LOADED TRAP. The coiled thread is the harpoon/mechanism, and discharge is like firing/snapping.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation of the morphemes ('thread' + 'bladder'). The standard Russian equivalent is 'книдоцит' or more specifically 'стрекательная клетка'.
Common Mistakes
- Using 'nematocyst' to refer to the sting of a non-cnidarian (e.g., a bee or stingray).
- Pronouncing it as /niːˈmætəˌsɪst/ (with a long 'ee' sound).
Practice
Quiz
What is a nematocyst?
FAQ
Frequently Asked Questions
No. The cnidocyte is the cell that contains the nematocyst (the stinging organelle). The nematocyst is the capsule inside the cell.
Yes. Physical or chemical contact with a cnidarian's tentacle can cause nematocysts to fire, leading to a sting.
Only animals in the phylum Cnidaria, which includes jellyfish, corals, sea anemones, and hydras.
Treatment varies by species. General advice often involves rinsing with vinegar (for some types) or seawater (not freshwater), carefully removing tentacles, and applying heat or cold as recommended for the specific sting.