What is "limb of the law"

Limb \Limb\ (l[i^]m), n. [OE. lim, AS. lim; akin to Icel. limr limb, lim branch of a tree, Sw. & Dan. lem limb; cf. also AS. li[eth], OHG. lid, gilid, G. glied, Goth. li[thorn]us. Cf. Lith, Limber.]

1. A part of a tree which extends from the trunk and separates into branches and twigs; a large branch.

2. An arm or a leg of a human being; a leg, arm, or wing of an animal.

   A second Hector for his grim aspect, And large proportion of his strong-knit limbs.
   --Shak.

3. A thing or person regarded as a part or member of, or attachment to, something else.
   --Shak.

   That little limb of the devil has cheated the gallows.
   --Sir W. Scott.

4. An elementary piece of the mechanism of a lock.

   Limb of the law, a lawyer or an officer of the law. [Colloq.]
   --Landor.