apsis

noun 0.748

periastron

noun 0.735

perigee

noun 0.715

perihelion

noun 0.701

pericenter

noun 0.677

apogee

noun 0.639

aphelion

noun 0.623

closest point of approach

noun 0.586

semimajor axis

noun 0.504

mesopause

noun 0.503