The Collaborative International Dictionary of English v.0.48:

Allocatur \Al`lo*ca"tur\, n. [LL., it is allowed, fr. allocare
   to allow.] (Law)
   "Allowed." The word allocatur expresses the allowance of a
   proceeding, writ, order, etc., by a court, judge, or judicial
   officer.
   [1913 Webster]

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

ALLOCATUR, practice. The allowance of a writ; e. g. when a writ of habeas
corpus is prayed for, the judge directs it to be done, by writing the word
allowed and signing his name; this is called the allocator. In the English
courts this word is used to indicate the master or prothonotary's allowance
of a sum referred for his consideration, whether touching costs, damages, or
matter of account. Lee's Dict. h, t.