from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The furthest point of an astronomical object in an elliptical orbit to its center of attraction (the principal focus of the ellipse)
from The Century Dictionary and Cyclopedia
- n. In the orbit of a heavenly body, the point most distant from the body or point around which it revolves.
- n. In biology, an organism or organ which may be regarded as a specialized or divergent descendant from a more primitive or less specialized organism or organ.
apo- + center (Wiktionary)