Apperception \Ap`per*cep"tion\, n. [Pref. ad- + perception: cf. F. apperception.]

(Metaph.) The mind's perception of itself as the subject or actor in its own states; perception that reflects upon itself; sometimes, intensified or energetic perception. --Leibnitz. Reid.

This feeling has been called by philosophers the apperception or consciousness of our own existence. --Sir W. Hamilton.

Source: Webster's Revised Unabridged Dictionary (1913)