noun · 2 senses · updated from the 2026-07-25 local source snapshot
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Pronunciation
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Received-Pronunciation:/pləˈnɛə.ɹi.ən/
General-American:/pləˈnɛ.ɹi.ən/
rhymes with -ɛəɹiən
CMU ARPABET:P L AH0 N EH1 R IY0 AH0 N
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
Any of various flatworms of the order Tricladida living in marine, freshwater, or terrestrial environments.
Definition source: English Wiktionary via Wiktextract
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
2
noun
Meaning 2
free-swimming mostly freshwater flatworms; popular in laboratory studies for the ability to regenerate lost parts
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: planaria
Antonyms: none provided
Broader terms: flatworm, platyhelminth
History
Etymology
From translingual Planaria (genus) (from Late Latin plānārius (“lying on a plane”), from Latin plānum) + -an.
Across languages
Translations
6 source translations are retained for this English entry.