planetary

adjective

plan·​e·​tary ˈpla-nə-ˌter-ē 

1

a

: of, relating to, being, or resembling a planet

b

: erratic, wandering

c

: having a motion like that of a planet

planetary electrons

d

: immense

the scope of this project has reached planetary proportions

2

a

: of, relating to, or belonging to the earth : terrestrial

b

: global, worldwide

planetary politics

3

: having or consisting of an epicyclic train of gear wheels

Synonyms of planetary

• vast
• giant
• huge
• gigantic
• astronomical
• tremendous
• enormous
• massive
• colossal
• mammoth
• monumental
• bumper
• immense
• cosmic
• galactic
• titanic
• mountainous
• oceanic
• monster
• grand
• monstrous

Examples of planetary in a Sentence

a positively planetary new shopping development

Recent Examples on the Web

The observations will be important for lunar and planetary scientists. —Denise Chow, NBC news, 7 Apr. 2026

Major projects in development include the Nancy Grace Roman Space Telescope — which is expected to launch later this year — as well as planetary missions like Dragonfly, which is aimed for Saturn's largest moon, Titan, and the asteroid-hunting Near-Earth Object (NEO) Surveyor. —Samantha Mathewson, Space.com, 6 Apr. 2026

Jim Head, a professor of planetary geosciences at Brown University was there for them all. —Brandon Truitt, CBS News, 6 Apr. 2026

Both crater names have to be approved by the International Astronomical Union, which is responsible for naming planetary surface features. —Stevie Bonifield, The Verge, 6 Apr. 2026

Word History

First Known Use

1607, in the meaning defined at sense 1a

Phrases Containing planetary

• planetary nebula
• planetary science

Rhymes for planetary

• accessary
• adversary
• ancillary
• arbitrary
• aviary
• axillary
• beriberi
• breviary
• budgetary
• capillary
• catenary
• cautionary

Kids Definition

planetary

adjective

plan·​e·​tary ˈplan-ə-ˌter-ē 

1

a

: of or relating to a planet

b

: having a motion like that of a planet

planetary electrons of the atomic nucleus

2

: worldwide, global

a matter of planetary concern