Dictionary
Find
in
Dictionary
Thesaurus
Translations

Click to move up the list of words
pericope
pericranium
pericycle
periderm
peridium
peridot
peridotite
perigee
Périgueux
perigynous
perihelion
perikaryon
peril
peril point
perilla
perilous
perilune
Click to move down the list of words
Also available:

World English Dictionary
Dictionnaire Français

periastron

per·i·as·tron [ pèrree ástrən, pèrree á stròn ] (plural per·i·as·trons)


noun 
Definition:
 
points when stars are nearest: the points in space and time in the orbits of two stars in a binary system at which they are closest together

[Mid-19th century. <peri- + Greek astron "star," after perihelion]
Advertisement

© 2009 Microsoft