Source : Webster's Revised Unabridged Dictionary (1913)

Dilogy \Dil"o*gy\, n.; pl. {Dilogies}. [L. dilogia, Gr. ?, fr. ?
   doubtful; di- = di`s- twice + ? to speak.] (Rhet.)
   An ambiguous speech; a figure in which a word is used an
   equivocal sense. [R.]