Astro?

So there was recently a discussion, during a party game, on whether or not "astro" is a word all by itself. And I am not referring to any sports teams. Vote what you think in the comments.

astro-
prefix
Definition:
1. star, the stars, outer space
astrobiology
2. aster of a cell
astrocyte
[< Greek< astron "star" < astēr (see aster)]
Definition found at www.encarta.msn.com

OR

Main Entry: astr-
Variant(s): or astro-
Function: combining form
Etymology: Latin astr-, astro-, from Greek, from astronomy — more at star
: star : heavens : outer space : astronomical
Definition found at http://www.merriam-webster.com/dictionary/

THEN:
combining form : a linguistic form that occurs only in compounds or derivatives and can be distinguished descriptively from an affix by its ability to occur as one immediate constituent of a form whose only other immediate constituent is an affix (as cephal- in cephalic) or by its being derived from an independent word (as electro- representing electric in electromagnet or para- representing parachute in paratrooper) or can be distinguished historically from an affix by the fact that it is borrowed from another language in which it is descriptively a word or a combining form (as French mal giving English mal- in malodorous)

I love you Honey. :)