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

That's 12 times brighter than its nearest planetary competitor, Jupiter and a full 25 times more dazzling than Sirius, the brightest of all stars. — Joe Rao, Space.com, 6 Nov. 2026

Earth's ozone layer acts as a planetary sunscreen, shielding humans, animals, and plants from harmful ultraviolet (UV) radiation. — Dan Peck, ABC News, 4 Nov. 2026

Benna, a planetary scientist with the University of Maryland, Baltimore County (UMBC) and NASA, described the instrument as a toolbox. — CBS News, 4 Nov. 2026

The simulation reproduced 19 planetary properties, including heat flow through Earth’s mantle. — Neetika Walter, Interesting Engineering, 3 Nov. 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