A more thorough explanation:

Communis opinio doctorum is a Latin term that means "learned common opinion." It refers to the scholarly agreement on points of Roman law that was collected by the glossators of Justinian's texts in the later Middle Ages.

An example of communis opinio doctorum is the agreement among legal scholars that a contract must have a valid offer, acceptance, and consideration to be enforceable. Another example is the consensus that a person cannot be punished twice for the same crime, known as double jeopardy.

These examples illustrate how legal scholars have reached a common understanding of certain principles of Roman law through their study and analysis of Justinian's texts. This shared knowledge forms the basis of modern legal systems in many countries.