A more thorough explanation:

Definition: A certificate of protest is a notice to the indorser of an instrument (such as a check or promissory note) that acceptance or payment has been refused. This notice is a condition of an indorser's secondary liability, along with presentment and actual dishonor. It is also known as a notice of dishonor or certificate of dishonor.

Example: If a person writes a check to another person, and the bank refuses to honor the check due to insufficient funds, the bank will issue a certificate of protest to the person who wrote the check. This notice informs the person that the check was not honored and that they are responsible for making good on the payment.

Explanation: The example illustrates how a certificate of protest is used in the case of a dishonored check. The bank sends a notice to the person who wrote the check, informing them that the check was not honored and that they are responsible for making good on the payment. This notice is a condition of the indorser's secondary liability, which means that they are responsible for paying the amount of the check if the person who received the check cannot or will not pay it.