WordNet (r) 3.0 (2006):

batting average
    n 1: (baseball) a measure of a batter's performance; the number
         of base hits divided by the number of official times at
         bat; "Ted Williams once had a batting average above .400"
         [syn: batting average, hitting average]
    2: (an extension of the baseball term) the proportion of times
       some effort succeeds; "the salesman's batting average was 7
       out of 12"