Definition

1. Adjective:
   • Relating to or resembling a planet: Pertaining to the physical characteristics, motion, or orbital path of a planet or planets.
   • Of or relating to the entire Earth; global: Involving the whole world or its inhabitants; having worldwide scope or significance.
   • Erratic; wandering: Having no fixed course; moving or behaving in an unpredictable or irregular manner.

Examples of Usage

• Relating to a planet:
  • Planetary motion is governed by the laws of gravity.
  • Scientists study the planetary atmosphere of Mars.
• Global; relating to Earth:
  • Climate change is a planetary crisis.
  • The invention had planetary significance.
• Erratic; wandering:
  • (Archaic/Literary) He led a planetary existence, never settling in one place.
  • The planetary vagabond roamed from town to town.

Advanced Usage

• "Planetary science": The scientific study of planets, moons, and planetary systems.
  • She majored in planetary science to become an expert on Mars.
• "Planetary scale": On a scale as large as a planet; having a global impact.
  • The pandemic was a challenge of planetary scale.
• "Planetary nebula" (Astronomy): A glowing shell of ionized gas ejected from red giant stars late in their lives. (Note: This is a compound term where "planetary" describes a type of nebula, historically named for its round, planet-like appearance through telescopes).

Variants and Related Words

• Planet (n): A celestial body moving in an orbit around a star.
• Interplanetary (adj): Situated or traveling between planets.
  • Interplanetary space travel is a goal for many agencies.
• Extraplanetary (adj): Originating or existing outside a planet.
  • The search for extraplanetary life continues.

Synonyms

• Global: Worldwide, international.
• Terrestrial: Earthly, worldly (specifically relating to Earth).
• Erratic: Wandering, nomadic, vagabond.

Related Phrases

• Planetary alignment: An astronomical event where planets appear in a line in the sky.
  • The planetary alignment was visible just before dawn.
• Planetary gear (Engineering): A gear system consisting of one or more outer gears revolving around a central "sun" gear.
  • The car's transmission uses a complex planetary gear set.

Related Idioms

• "It's not planetary": (Informal, humorous) Used to indicate something is not of great, world-altering importance.
  • Relax, forgetting your keys is not a planetary emergency.

Adjective

1. involving the entire earth; not limited or provincial in scope
   • global war
   • global monetary policy
   • neither national nor continental but planetary
   • a world crisis
   • of worldwide significance
2. having no fixed course
   • an erratic comet
   • his life followed a wandering course
   • a planetary vagabond
3. of or relating to or characteristic of the planet Earth or its inhabitants
   • planetary rumblings and eructations- L.C.Eiseley
   • the planetary tilt
   • this terrestrial ball
4. of or relating to or resembling the physical or orbital characteristics of a planet or the planets
   • planetary motion
   • planetary year