batting average

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A measure of a batter's performance obtained by dividing the total of base hits by the number of times at bat, not including walks, sacrifices, times hit by a pitch, or times interfered with by the catcher.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun cricket A statistical estimation of the scoring ability of a batsman; equal to the total number of runs scored divided by the number of times out.
• noun baseball A statistical estimation of the hitting ability of a batter; equal to the number of hits divided by the number of official at-bats. Normally expressed as a real number instead of an average despite the name.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (an extension of the baseball term) the proportion of times some effort succeeds
• noun (baseball) a measure of a batter's performance; the number of base hits divided by the number of official times at bat