1. Of or relating to the earth or its inhabitants.
2. Biology Living or growing on land or on or in the ground; not aquatic, arboreal, or epiphytic: terrestrial mammals; terrestrial apes; terrestrial orchids.
3. Astronomy Similar to the planet earth in size or composition: terrestrial planets.
4. Transmitted from structures on the earth and not involving satellites: terrestrial radio.
5. Archaic Of or relating to the earth rather than heaven.
An inhabitant of the earth.
[Middle English, from Latin terrestris, from terra, earth; see ters- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.