A more thorough explanation:

Definition: Correal (kor-ee-uhl or kuh-ree-uhl) is an adjective that comes from the Latin word "correus," which means "codebtor." In Roman law, it refers to liability that is joint and several.

Example: If Aulus borrowed 100 aurei from Titius and then turned to Seius and asked, "Do you engage, Seius, to give me the same one hundred aurei?" and Seius answered, "I engage," then there was one single obligation for a hundred aurei, binding in full on each of the two debtors. Aulus could demand a hundred from Titius or a hundred from Seius, and in case of non-payment could sue either one, taking his choice between them, for the full amount. If either paid the hundred, whether willingly or by compulsion, the other was released: for there was but one debt, and that was now discharged. This kind of obligation is called correal obligation.

Explanation: The example illustrates how correal liability works in Roman law. Aulus borrowed money from two people, Titius and Seius, and they both became codebtors. Aulus could demand payment from either one of them, and if one paid, the other was released from the debt. This is an example of correal liability because both Titius and Seius were jointly and severally liable for the debt.