Definition 1:
A certificate is a written statement, signed by an official, describing acts performed in an official capacity.
Definition 2:
A notary certificate would generally include a venue which would indicate the state and county where the notary act took place, notary wording indicating who the signer was, the date the notarization took place, a signature of the notary, and additional boiler plate wording would be standard components of the many varieties of notary certificates. Notary certificates could be designated for many of the possible notary acts and could differ somewhat in content from state to state. In many states, a Notary certificate must be attached ( generally by staple ) to the document it is associated with, after the notarization has been completed.
Definition 3:
A piece of paper with notarial wording that is attached to a notarized document. The wording could be included at the end of the document instead of being on a seprate piece of paper.