The Collaborative International Dictionary of English v.0.48:

Praecipe \Pr[ae]c"i*pe\, n. [L., imperative of praecipere to
   give rules or precepts. See Precept.] (Law)
   (a) A writ commanding something to be done, or requiring a
       reason for neglecting it.
   (b) A paper containing the particulars of a writ, lodged in
       the office out of which the writ is to be issued.
       --Wharton.
       [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

PRAECIPE or PRECIPE, practice. The name of the written instructions given by
an attorney or plaintiff to the clerk or prothonotary of a; court, whose
duty it is to make out the writ, for the making of the same.