A more thorough explanation:

Definition: An authentic act is a written document that is signed before a notary public or other public officer.

Example: A person signs a contract in front of a notary public, who then signs and stamps the document to make it an authentic act.

Explanation: An authentic act is a legal document that has been verified by a public officer, such as a notary public. This ensures that the document is genuine and can be used as evidence in court if necessary. The example shows how a contract can become an authentic act by being signed in front of a notary public.