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

Johannes Kepler, the German polymath famous for his laws of planetary motion, conjectured that this arrangement was optimal back in 1611. — Jack Murtagh, Scientific American, 17 Sep. 2026

Building a census of planetary systems Ultimately, Roman serves as an example of why using several planet-hunting techniques matters. — Thomas Fauchez, The Conversation, 14 Sep. 2026

But craters and debris from billions of years of impacts covered many of these fissures, said lead study author Gaku Nishiyama, a planetary scientist at the German Aerospace Center’s Institute of Space Research in Berlin. — Ashley Strickland, CNN Money, 10 Sep. 2026

According to Hou, Mars sample return is an extremely complex project, with landing-site selection, planetary protection and contamination control, and the identification of potential signs of life among its key challenges. — Leonard David, Space.com, 9 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