Ab Katan

Ab Katan (Hebrew: אב קטן, meaning "minor father") is a term used in Jewish law (Halakha) to refer to an indirect source of melacha (forbidden labor) on Shabbat. It is one level removed from a melacha d'oraita (a biblically prohibited labor) and generally considered a melacha d'rabbanan (a rabbinically prohibited labor).

The distinction between melacha d'oraita, ab melacha (primary forbidden labor), ab katan, and toladah (derivative labor) is crucial in determining the severity of the prohibition and the appropriate response if one is inadvertently performed on Shabbat. Ab Katan activities, while forbidden, are typically considered less severe than their ab melacha counterparts. The classification of an action as ab katan or toladah often depends on the specific circumstances and the interpretation of the relevant rabbinic authorities.

Examples of actions that might be categorized as ab katan can vary depending on the specific melacha being considered and the interpretation of Jewish law. The determination often revolves around how directly the action replicates or contributes to the primary forbidden labor.

It is important to consult with a knowledgeable rabbi or posek (Halakhic authority) for guidance on specific questions regarding ab katan and its application to particular situations.