Gaia n.

"pertaining to the earth," 1846, from -ian + Latin tellus (genitive telluris) "earth, land, ground; the earth" (related to Tellus, Roman goddess of the earth), probably from PIE root *telho- "ground, floor" (source also of Sanskrit talam "plain, sole of the foot;" Greek telia "dice board;" Latvian telint "to spread out;" Lithuanian tils "bottom of a barge, flooring," patalas "bed;" Old Prussian tallus "floor;" Old Church Slavonic tilo "floor;" Russian potolok "ceiling;" Old Irish talam "earth;" Old Norse ilja, Middle Dutch dele "plank").  Or possibly from PIE  *telh- "to bear." As a noun, "inhabitant of Earth" (with reference to supposed inhabitants of other worlds) from 1847.

"point at which the moon is farthest from the earth," 1590s, from French apogée or directly from Latin apogaeum, from Greek apogaion (diastema) "(distance) away from the earth," from apogaion, neuter adjective, "from land," here in a specialized sense "away from the earth," from apo "off, away" (see apo-) + gaia/ge "earth" (see Gaia).

The figurative sense of "climax, culmination" is from 1640s. A term from Ptolemaic astronomy, which regarded the earth as the center of the universe and applied the word to the sun and planets; for these bodies it was displaced in the Copernican system by aphelion. Adjective forms are apogeal, apogean, apogeic.