The Collaborative International Dictionary of English v.0.48:

Quantify \Quan"ti*fy\, v. t. [L. quantus now much + -fy.]
   1. To modify or qualify with respect to quantity; to
      determine, fix or express the quantity of; to rate.
      [1913 Webster]

   2. (Logic) To make explicit the quantity of; as, to quantify
      a variable.
      [PJC]

WordNet (r) 3.0 (2006):

quantify
    v 1: use as a quantifier
    2: express as a number or measure or quantity; "Can you quantify
       your results?" [syn: quantify, measure]

The Free On-line Dictionary of Computing (19 January 2023):

Quantify

   A performance analysis tool from Pure Software.