An Etymological Dictionary of Astronomy and Astrophysics

The point in the orbit of a satellite around the Moon closest to the Moon; opposite of → apocynthion.

Etymology (EN): → peri- + Gk. Cynthia “goddess of the Moon;”
→ Cynthian.

Etymology (PE): Pirâmâh, from pirâ-, → peri-, + mâh→ moon.