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

Studying these alien auroras helps researchers better understand planetary atmospheres and magnetic fields. —Kaif Shaikh, Interesting Engineering, 15 June 2026

The slow dance came to a climax on June 9 — which is depicted in the far right panel — when skywatchers worldwide were treated to a dramatic planetary conjunction as Jupiter and Venus shone less than 2 degrees away from one another above the western horizon. —Anthony Wood, Space.com, 13 June 2026

This open optical ecosystem gives the C42 immense room to grow, supporting everything from a 14-mm ultra-wide nightscape lens to a massive 2,000-mm+ planetary setup on an advanced equatorial mount. —New Atlas, 12 June 2026

But asteroids have their own problems, and a radical new idea about planetary water is gaining steam. —Quanta Magazine, 12 June 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