The Collaborative International Dictionary of English v.0.48:

Thrave \Thrave\ (thr[=a]v), n. [OE. [thorn]rave, [thorn]reve,
   Icel. [thorn]refi; akin to Dan. trave; cf. Icel.
   [thorn]r[imac]fa to grasp.]
   1. Twenty-four (in some places, twelve) sheaves of wheat; a
      shock, or stook. [Prov. Eng.]
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   2. The number of two dozen; also, an indefinite number; a
      bunch; a company; a throng. "The worst of a thrave."
      [Obs.] --Landsdowne MS.
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            He sends forth thraves of ballads to the sale. --Bp.
                                                  Hall.
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