Cessor is a related term of cesser.

In lang=en terms the difference between cesser and cessor

is that cesser is a neglect of a tenant to perform services, or make payment, for two years while cessor is in English law, one who is dilatory, negligent, and delinquent in his duty or service, and who thereby incurred the danger of the law, and was liable to have the writ of cessavit brought against him.