Source : Webster's Revised Unabridged Dictionary (1913)

Anteriority \An*te`ri*or"i*ty\, n. [LL. anterioritas.]
   The state of being anterior or preceding in time or in
   situation; priority. --Pope.

Source : WordNet®

anteriority
     n 1: the quality of being in front or (in lower animals) toward
          the head [ant: {posteriority}]
     2: preceding in time [syn: {priority}, {antecedence}, {antecedency},
         {precedence}, {precedency}] [ant: {posteriority}]