(lit. "father of work"). Any of the 39 categories of work prohibited on the Sabbath. While the Fourth Commandment forbids work on the Sabbath, there is no definition in the Ten Commandments as to what constitutes "work." Based on the juxtaposition between three verses in Exodus (35:1-3) dealing with the prohibition against working on the Sabbath and the verses which immediately follow (4ff.), which deal with erecting the Tabernacle (mishkan; see Sanctuary), the Talmud (Shab. 49b) concludes that while erecting the Tabernacle was commanded by God, the work on the Tabernacle had to cease on the Sabbath. "Work" on the Sabbath is thus defined as any type of work that was required in the construction of the Tabernacle, and is accordingly forbidden on the Sabbath. As the Talmud puts it, "They sowed [i.e., on weekdays, to grow plants needed for the incense], so you may not sow [on the Sabbath]; they reaped ..." etc. Each type of work listed in the Mishnah (Shab. 7:2) as being biblically forbidden on the Sabbath is referred to as an av melakhah, or primary category of work.
Each av melakhah has toledot, or "derivitives." Each of these toledot is related to a specific av melakhah, in that it resembles the av melakhah type of work. The toledot, too, are biblically proscribed on the Sabbath. For example, one of the avot melakhah is plowing, so that breaking up clumps of earth as such on the Sabbath would be a toledah. As far as Jewish law is concerned, the difference is only in nomenclature, for the punishment for violating a toledah is the same as for violating an av melakhah.
