A more thorough explanation:

Collatio signorum is a Latin term used in law, which means "comparison of signs". It refers to a historical method of testing the authenticity of a seal by comparing it with another seal that is known to be genuine.

For example, in ancient times, when a document was sealed with a wax seal, the authenticity of the seal was important to ensure that the document was not tampered with. To test the authenticity of the seal, a collatio signorum was performed by comparing the seal in question with another seal that was known to be genuine. If the two seals matched, it was assumed that the seal in question was also genuine.

Another example of collatio signorum is in modern times, when a bank verifies the authenticity of a customer's signature on a check. The bank compares the signature on the check with the signature on file for the customer to ensure that the check is not fraudulent.

The examples illustrate the definition of collatio signorum by showing how it was used in ancient times to test the authenticity of seals and how it is still used today to verify signatures. The method involves comparing the seal or signature in question with another that is known to be genuine, to ensure that it is not a forgery. This method is still used today in various forms to ensure the authenticity of important documents and transactions.