earned run average
noun Baseball.
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. Abbreviation: ERA, era
Origin of earned run average
First recorded in 1945–50
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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019