Pertaining to civil suits in "equity" rather than in "law." In English legal history, the courts of "law" could order the payment of damages and could afford no other remedy (see damages). A separate court of "equity" could order someone to do something or to cease to do something (e.g., injunction). In American jurisprudence, the federal courts have both legal and equitable power, but the distinction is still an important one. For example, a trial by jury is normally available in "law" cases but not in "equity" cases.
Source: US Courts Glossary
