Meaning of earned run average

earned' run' av"erage

Pronunciation: [key]
— Baseball. Baseball.
  1. a measure of the effectiveness of a pitcher, obtained by dividing the number of earned runs scored against the pitcher by the number of innings pitched and multiplying the result by nine. A pitcher yielding three earned runs in nine innings has an earned run average of 3.00. Abbr.: ERA, era
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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