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

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

Examples of planetary in a Sentence

a positively planetary new shopping development

Recent Examples on the Web

The fashionably late arrival of oxygen may sound like a planetary sigh of relief. —Laura Poppick, Rolling Stone, 30 June 2025

There have been a number of missions in the past that have used this technique for things like mapping planetary gravitational anomalies and magnetic fields, but that doesn't make things any easier. —David Szondy june 28, New Atlas, 28 June 2025

The new research finds that our own fair world has a 0.2 percent chance of being involved in a planetary collision or ejected into interstellar space. —Phil Plait, Scientific American, 26 June 2025

The next major planetary conjunctions will see Venus and Jupiter appear to be just 2.4 degrees apart before sunrise on Aug. 12 and a crescent moon and Venus just 0.8 degrees apart before sunrise on Sept. 19. —Jamie Carter, Forbes.com, 26 June 2025

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