• (n.) Concurrence of starry position or influence; hence, similarity of condition, fortune, etc., as prefigured by astrological calculation. Found on http://thinkexist.com/dictionary/meaning/synastry/
Syn'as·try noun [ Prefix syn- + Greek ... a star.] Concurrence of starry position or influence; hence, similarity of condition, fortune, etc., as prefigured by astrological calculation. [ R.] Motley. Found on http://www.encyclo.co.uk/webster/S/264