Uniform Contribution Among Tortfeasors Act (1955)

Many states have adopted in part or in whole the Uniform Contribution Among Tortfeasors Act.

Note that the term pro rata share refers to an equal division of liabilty among defendants. For example, if three defendants are found jointly and severally liable, the pro rata share of each would be one third.

Note also that the terms "joint" and "several" liabilty have various (and sometimes contradictory) meanings in different jurisdictions. Traditionally, at common law, the term "joint and several liability" meant that a plaintiff could bring a single "joint" action against all defendants who were each "severally" liable for the full amount of the plaintiff's damages vis-a-vis the plaintiff. That is, the plaintiff could recover all of their  damages from one or any combination of defendants, up to the amount awarded by the court. (The plaintiff can never recover more than this amount.) Any defendant who paid more than their fair share could file a separate action for "contribution" against other defendants for reimbursement.

By contrast, some jurisdictions today use the term "joint liabilty" to denote that each defendant is liable for the full amount of the plaintiff's damages vis-a-vis the plaintiff (this is equivalent to the meaning of the traditional common law term "joint and several liability") and the term "several liability" to denote that each defendant is liable vis-a-vis the plaintiff for only their pro rata or proportional share of the damages (the opposite of the meaning of the traditional common law term "joint and several liability").

When you read these terms, be sure you know what they mean, and when you use them, be sure to clarify what you  mean by them.