Neptune

noun

Nep·​tune ˈnep-ˌtün 

-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

nep-ˈtü-nē-ən 

-ˈtyü-

adjective

Synonyms

• sea
• ocean

Examples of Neptune in a Sentence

sailors shipwrecked by the wild waves of Neptune

Recent Examples on the Web

The study stated that the planets are actually a similar shade of greenish blue, and that the error was down to inaccurate color in NASA’s Voyager 2's camera, which captured Uranus and Neptune in 1986 and 1989, respectively. —Jamie Carter, Forbes.com, 6 Aug. 2025

My Oxford Year crew also traveled to Windsor to utilize the takeaway restaurant King Neptune Fish and Chip Shop. —Caroline Blair, People.com, 5 Aug. 2025

With Neptune entering Aries on the 30th, your vision for the future is starting to expand. —Meghan Rose, Glamour, 1 Aug. 2025

As Venus clashes with Saturn and Neptune, romance seems out of reach. —Usa Today, USA Today, 1 Aug. 2025

Word History

Etymology

Latin Neptunus

First Known Use

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

Kids Definition

Neptune

noun

Nep·​tune ˈnep-ˌt(y)ün 

: the planet eighth in order from the sun see planet

Neptunian

nep-ˈt(y)ü-nē-ən 

adjective