adj · noun · 12 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:/nɛpˈtjuː.nɪ.ən/
Received-Pronunciation:Recorded audio is listed in the source snapshot.
General-American:/nɛpˈt(j)u.ni.ən/
General-American:/-ˈtʃuː-/
1
adj
Meaning 1
Of or pertaining to Neptune, the Roman god of fresh water and the sea, the counterpart of the Greek god Poseidon.
Definition source: English Wiktionary via Wiktextract
Definition source: English Wiktionary via Wiktextract
Usage: broadly, not-comparable, rare
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
3
adj
Meaning 3
Formed by the action of water.
Definition source: English Wiktionary via Wiktextract
Usage: broadly, not-comparable
Topics: geography, geology, natural-sciences
Examples
neptunian dyke
Meaning relationships
Synonyms: none provided
Antonyms: none provided
4
adj
Meaning 4
Of, pertaining to, or supporting Neptunism (“a discredited theory that rocks were formed from the crystallisation of minerals in the early Earth's oceans”).
Definition source: English Wiktionary via Wiktextract
Usage: broadly, historical, not-comparable
Topics: geography, geology, natural-sciences
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
5
adj
Meaning 5
Pertaining to the astrological influence of the planet Neptune.
Definition source: English Wiktionary via Wiktextract
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
12
noun
Meaning 12
Alternative letter-case form of Neptunian.
Definition source: English Wiktionary via Wiktextract
Usage: alt-of
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
History
Etymology
From Latin Neptūnius (“of or pertaining to the Roman god Neptune”), from Neptūnus (“the Roman god Neptune”) (possibly ultimately from Proto-Indo-European *nebh- (“to become damp, cloudy”)) + -ius (suffix forming adjectives from nouns); analysable as Neptune + -ian. The English word is cognate with French neptunien (“pertaining to the Roman god Neptune, pertaining to the sea, pertaining to Neptunism, Neptunian; proponent of Neptunism, Neptunist”), German Neptunier (“proponent of Neptunism, Neptunist”).
From Neptune (“eighth planet in the solar system”) + -ian.
Across languages
Translations
35 source translations are retained for this English entry.
Catalan:
neptunià
— of or pertaining to the Roman god Neptune
Catalan:
neptúnic
— of or pertaining to the Roman god Neptune
French:
neptunien
— of or pertaining to the Roman god Neptune
Italian:
nettunio
— of or pertaining to the Roman god Neptune
Bulgarian:
океански
(okeanski)
— of or pertaining to water or the sea
Bulgarian:
морски
(morski)
— of or pertaining to water or the sea
French:
neptunien
— of or pertaining to water or the sea
Italian:
nettunio
— of or pertaining to water or the sea
Catalan:
neptúnic
— formed by the action of water
Italian:
nettunico
— formed by the action of water
French:
neptunien
— of, pertaining to, or supporting Neptunism
German:
Neptunisch
— of, pertaining to, or supporting Neptunism
Italian:
nettuniano
— of, pertaining to, or supporting Neptunism
Arabic:
نِبْتُونِيّ
(nibtūniyy)
— of or pertaining to the planet Neptune
Basque:
neptunoar
— of or pertaining to the planet Neptune
Catalan:
neptúnic
— of or pertaining to the planet Neptune
Finnish:
Neptunukseen liittyvä
— of or pertaining to the planet Neptune
Finnish:
neptunuslainen
— of or pertaining to the planet Neptune
German:
neptunisch
— of or pertaining to the planet Neptune
Italian:
nettunense
— of or pertaining to the planet Neptune
Italian:
nettuniano
— of or pertaining to the planet Neptune
Portuguese:
netuniano
— of or pertaining to the planet Neptune
Spanish:
neptuniano
— of or pertaining to the planet Neptune
Welsh:
Neifionaidd
— of or pertaining to the planet Neptune
French:
neptunien
— proponent of Neptunism
French:
neptunienne
— proponent of Neptunism
German:
Neptunier
— proponent of Neptunism
German:
Neptunist
— proponent of Neptunism
Italian:
nettunista
— proponent of Neptunism
Arabic:
نِبْتُونِيّ
(nibtūniyy)
— inhabitant of the planet Neptune
Chinese Mandarin:
海王星人
(hǎiwángxīngrén)
— inhabitant of the planet Neptune
French:
Neptunien
— inhabitant of the planet Neptune
French:
Neptunienne
— inhabitant of the planet Neptune
Irish:
Neiptiúnach
— inhabitant of the planet Neptune
Japanese:
海王星人
(Kaiōsei-jin)
— inhabitant of the planet Neptune