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

Glimpsing many in the sky at once is a fun way to connect with astronomers of centuries past, said planetary scientist Emily Elizondo with Michigan State University. —Adithi Ramakrishnan, Los Angeles Times, 24 Feb. 2026

This celestial skew likely came from Uranus being pummeled by a huge planetary collision early in solar system history, and gives the ice giant strange seasons that span 42 Earth years. —Lee Billings, Scientific American, 24 Feb. 2026

What happens during a planetary alignment? —Janet Loehrke, USA Today, 24 Feb. 2026

The study also provides new insight into how stellar winds shape planetary environments and may influence the habitability of worlds around other stars. —Samantha Mathewson, Space.com, 24 Feb. 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