The Collaborative International Dictionary of English v.0.48:

Ampliation \Am`pli*a"tion\, n. [L. ampliatio: cf. F.
   ampliation.]
   1. Enlargement; amplification. [R.]
      [1913 Webster]

   2. (Civil Law) A postponement of the decision of a cause, for
      further consideration or re-argument.
      [1913 Webster]

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

AMPLIATION, civil law. A deferring of judgment until the cause is further
examined. In this case, the judges pronounced the word amplius, or by
writing the letters N.L. for non liquet, signifying that the cause was not
clear. In practice, it is usual in the courts when time is taken to form a
judgment, to enter a curia advisare vult; cur. adv. vult. (q.v.)



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

AMPLIATION, French law. Signifies the giving a duplicate of an acquittance
or other instrument, in order that it may be produced in different places.
The copies which notaries make out of acts passed before them, and which are
delivered to the parties, are also called ampliations. Dict. de Jur. h.t.