Anamnesis is 1) the recollection or remembrance of the past; reminiscence. 2) Platonism. recollection of the Ideas, which the sould had known in a previous existence, especially by means of reasoning. 3) the medical history of a pacient. 4) Immunology. A prompt immune response to a previously encountered antygen. 5. (often initial capital letter) a prayer in a Eucharistic service, recalling the Passion, Resurrection, and Ascension of Christ.