Search Result for "periapsis": 
Wordnet 3.0

NOUN (1)

1. (astronomy) the point in an orbit closest to the body being orbited;
[syn: periapsis, point of periapsis]



WordNet (r) 3.0 (2006):

periapsis
    n 1: (astronomy) the point in an orbit closest to the body being
         orbited [syn: periapsis, point of periapsis] [ant:
         apoapsis, point of apoapsis]