You don’t have to be Perry Mason to figure this one out because of the similarity of the Latin words—literally “body”, “law” and “second”.
Corpus Juris Secundum (Body of the Law, Second Edition) is a well-known legal encyclopedia in use for many years, covering the basics of state and federal law and spanning over 160 bound volumes and hundreds of topics. CJS is still cited routinely in court briefs and judicial opinions, mostly for established general principles. And if you watch Perry Mason, you will see copies of CJS on his desk in the closing credits…
— BBC&B