interplanetary

adjective

in·​ter·​plan·​e·​tary ˌin-tər-ˈpla-nə-ˌter-ē 

: existing, carried on, or operating between planets

interplanetary dust

an interplanetary flight

interplanetary spacecraft

Examples of interplanetary in a Sentence

Recent Examples on the Web

Look for data on the interplanetary magnetic field’s Bz component, which determines how easily solar energy enters Earth’s magnetosphere. —Jamie Carter, Forbes.com, 27 Jan. 2026

One key indicator is the Bz component of the interplanetary magnetic field. —Valerie Mesa, PEOPLE, 19 Jan. 2026

While fuel-efficient and technologically feasible, this type of engine cannot achieve escape velocity from the Solar System, but remains a promising method for interplanetary missions. —Matthew S Williams, Interesting Engineering, 10 Jan. 2026

Yui's video kicked off with a dramatic display of zodiacal light, which formed as sunlight reflected off a cloud of interplanetary dust particles to form a column of light above the colorful arc of our Blue Marble. —Anthony Wood, Space.com, 10 Jan. 2026

Word History

First Known Use

1691, in the meaning defined above

Rhymes for interplanetary

• beneficiary
• bronchopulmonary
• evolutionary
• expeditionary
• extramedullary
• extraordinary
• extrapulmonary
• genitourinary
• geostationary
• hepatobiliary
• illocutionary
• insurrectionary

Kids Definition

interplanetary

adjective

in·​ter·​plan·​e·​tary

ˌint-ər-ˈplan-ə-ˌter-ē

: between planets

interplanetary space

interplanetary travel