Source : Webster's Revised Unabridged Dictionary (1913)

Lucidity \Lu*cid"i*ty\, n. [Cf. F. lucidit['e]. See {Lucid}.]
   The quality or state of being lucid.

Source : WordNet®

lucidity
     n 1: free from obscurity and easy to understand; the
          comprehensibility of clear expression [syn: {clarity}, {pellucidity},
           {clearness}, {limpidity}] [ant: {unclearness}, {obscureness}]
     2: a lucid state of mind; not confused