1. a. A public declaration or proclamation, written or spoken; esp. a printed declaration, explanation, or justification of policy issued by a head of state, government, or political party or candidate, or any other individual or body of individuals of public relevance, as a school or movement in the Arts.
b. In extended use: a book or other work by a private individual supporting a cause, propounding a theory or argument, or promoting a certain lifestyle
2. A proof, a piece of evidence. Obs. noun: plural manifestos or manifesoes