adj. 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. n. An inhabitant of the earth. [Middle English, from Latin terrestris, from terra, earth; see ters- in the Appendix of Indo-European roots.] ter·restri·al·ly adv. ter·restri·al·ness n. |
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