earned run average マイ単語帳に追加

防御率

(baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched.

ピッチャーの有効性の評価。自責点の平均した数が投手を務められた9イニング毎のためにピッチャーで許容したように、計算されます。