Source : Webster's Revised Unabridged Dictionary (1913)

Aridity \A*rid"i*ty\, n.; pl. {Aridities}. [L. ariditas, fr.
   aridus.]
   1. The state or quality of being arid or without moisture;
      dryness.

   2. Fig.: Want of interest of feeling; insensibility; dryness
      of style or feeling; spiritual drought. --Norris.

Source : WordNet®

aridity
     n 1: a condition yielding nothing of value [syn: {fruitlessness},
           {barrenness}] [ant: {fruitfulness}]
     2: a permanent absence of rainfall [syn: {aridness}]