Neptune

noun

Nep·​tune ˈnep-ˌtün How to pronounce Neptune (audio)
-ˌtyün
1
a
: the Roman god of the sea compare poseidon
b
: ocean
2
: the planet eighth in order from the sun see Planets Table
Neptunian adjective

Examples of Neptune in a Sentence

sailors shipwrecked by the wild waves of Neptune
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The planet’s large size – with a radius 2.6 times that of Earth – means that the planet’s interior likely contains a large mantle of high-pressure ice, like Neptune, according to astronomers. Eric Lagatta, USA Today, 19 Apr. 2025 The love planet will also conjunct Neptune on May 2, adding a magical, almost surreal quality to these connections. Valerie Mesa, People.com, 19 Apr. 2025 Astronomers think that this world could either be a smaller version of our solar system’s ice giant Neptune, called a mini-Neptune, or perhaps a rocky planet with no water but a massive hydrogen atmosphere, called a gas dwarf. Daniel Apai, The Conversation, 18 Apr. 2025 The exoplanet’s size appears to be between that of Earth and Neptune and belongs to a range that scientists have never seen up close. Meghan Bartels, Scientific American, 17 Apr. 2025 See All Example Sentences for Neptune

Word History

Etymology

Latin Neptunus

First Known Use

before the 12th century, in the meaning defined at sense 1a

Time Traveler
The first known use of Neptune was before the 12th century

Browse Nearby Words

Cite this Entry

“Neptune.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Neptune. Accessed 25 Apr. 2025.

Kids Definition

Neptune

noun
Nep·​tune ˈnep-ˌt(y)ün How to pronounce Neptune (audio)
: the planet eighth in order from the sun see planet
Neptunian adjective

More from Merriam-Webster on Neptune

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