Source : Webster's Revised Unabridged Dictionary (1913)

Trioctile \Tri*oc"tile\ (-[o^]k"t[i^]l), n. [Pref. tri- +
   octile.] (Astrol.)
   An aspect of two planets with regard to the earth when they
   are three octants, or three eighths of a circle, that is, 135
   degrees, distant from each other. --Hutton.