cetacean

cetacean — noun

IPA/sɪˈteɪ.ʃən/
KK[sɪtˈeʃən]IPA/sɪˈteɪ.ʃən/
  • cetaceansingular
  • cetaceansplural

1. a whale, dolphin, porpoise, or similar sea mammal that breathes air and feeds it

1.nounC1
Definition

a whale, dolphin, porpoise, or similar sea mammal that breathes air and feeds its young with milk

Example

The guide explained that dolphins are cetaceans, not fish.

classification: dolphins belong to the cetacean group

Researchers tagged two cetaceans before releasing them into deeper water.

Common collocations
  • cetacean species
  • cetacean population
  • injured cetacean
  • beached cetacean

Grammar Patterns

a cetacean

study cetaceans

injured cetacean

Usage Note

This word is mainly used in biology, conservation, and museum writing. In everyday speech, people usually say whale, dolphin, or porpoise instead of cetacean.

Common Mistakes

A cetacean is a kind of fish.
A cetacean is a kind of marine mammal.
Cetaceans live in water, but they breathe air and feed milk to their young.

cetacean — adjective

IPA/sɪˈteɪʃn/
KK[sɪtˈeʃən]IPA/sɪˈteɪʃn/

Synonym discussion

Sense: noun/1

For sense 1, cetacean is the scientific umbrella word for the group that includes whales, dolphins, and porpoises. Whale and dolphin each name only part of that group, so they are narrower and more common in everyday speech. Marine mammal is broader: it also includes animals such as seals and manatees, which are not cetaceans. Use cetacean when you want a technical label for the whole whale-and-dolphin family, especially in research, conservation, or museum contexts.

Common collocations

Nouns

  • cetacean species
  • cetacean population
  • cetacean research
  • cetacean stranding

Phrases

  • small cetacean
  • toothed cetacean
  • cetacean conservation

Etymology

GreekLatinEnglish

Cetacean comes from Latin cetaceus, meaning something belonging to whales, and that Latin word goes back to Greek ketos, a large sea creature or whale. English kept the scientific sense, so the word is still used mainly in biology and wildlife writing for the group that includes whales, dolphins, and porpoises.