cnidarian

Thân thiện

A marine biologist carefully observes a cnidarian in a clear aquarium tank.

Definition

Noun: A cnidarian is a member of the phylum Cnidaria, a group of simple, mostly marine animals characterized by radial symmetry, a sac-like body with a single opening serving as both mouth and anus, and specialized stinging cells called cnidocytes on their tentacles. They exist in two main body forms: the sessile polyp (e.g., sea anemone) and the free-swimming medusa (e.g., jellyfish).

Usage and Examples

• The jellyfish, a common cnidarian, can deliver a painful sting.
• Coral reefs are built by colonies of tiny cnidarian polyps.
• Scientists study the simple nervous system of the cnidarian to understand early animal evolution.

Advanced Usage

• The term is primarily used in formal, scientific, and zoological contexts.
• It can function attributively as a noun modifier (e.g., cnidarian biology, cnidarian venom).

Variants and Related Words

• Coelenterate (noun): An older, less precise taxonomic term that historically included cnidarians and ctenophores (comb jellies). "Cnidarian" is now the preferred scientific term.
• Cnidocyte (noun): The specialized stinging cell unique to cnidarians.
• Cnidaria (noun): The phylum name itself.

Different Meanings

The word "cnidarian" has a single, specific zoological meaning and is not used figuratively.

Synonyms

• Coelenterate (historical synonym, see note above)

Idioms and Phrases

There are no common idioms or phrasal verbs using the word "cnidarian," as it is a technical scientific term.

Học thuật

Noun

1. radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms

Từ đồng nghĩa

• coelenterate