Source : Webster's Revised Unabridged Dictionary (1913)

Proficience \Pro*fi"cience\, Proficiency \Pro*fi"cien*cy\, n.
   The quality of state of being proficient; advance in the
   acquisition of any art, science, or knowledge; progression in
   knowledge; improvement; adeptness; as, to acquire proficiency
   in music.

Source : WordNet®

proficiency
     n 1: the quality of having great facility and competence
     2: skillfulness in the command of fundamentals deriving from
        practice and familiarity; "practice greatly improves
        proficiency" [syn: {technique}]