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 most critical assessment comes from Chris McKay, a planetary scientist at NASA’s Ames Research Center, who has studied terraforming for decades. — Brian Gallagher, Scientific American, 2 Oct. 2026

Some of the debris swirling in the rotating disk is a remnant from planetary formation. — Jacopo Prisco, CNN Money, 2 Oct. 2026

Long, planetary waves push the warm water to our coast and also raise the sea level, according to Clarissa Anderson, director of the Southern California Coastal Ocean Observing System at UC San Diego’s Scripps Institution of Oceanography. — Lila Seidman, Los Angeles Times, 1 Oct. 2026

While designers have no current use for their jump-otronic robots, the sheer amount of robotics development for terrestrial and extra-planetary exploration suggests that the photoleapers are a solution that will eventually find their problem. — New Atlas, 28 Sep. 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
• apiary
• arbitrary
• aviary
• axillary
• bacillary
• beriberi
• bestiary
• breviary
• budgetary

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