Ex`o·rhi'za (ĕks`o*rī'zȧ) noun ; plural Exorhizæ (- zē). [ New Latin from Greek 'e`xw outside + 'ri`za root.] (Botany) A plant Whose radicle is not inclosed or sheathed by the cotyledons or plumule. Gray. Found on http://www.encyclo.co.uk/webster/E/88