A mistake or fault; commonly refers to a failure or exception in computer programs or machinery.
プログラムが実行時にエラーを出して落ちた。
The program threw an error at runtime and crashed.
保存ボタンを押すとエラーが表示された。
When I pressed the save button, an error was displayed.
エラーの原因はログを確認すればわかるはずだ。
You should be able to find the cause of the error by checking the logs.
In baseball, a defensive mistake (an error) such as a fumble or bad throw that allows a runner to advance.
第九回にセンターのエラーでランナーが進塁した。
In the ninth inning a center-field error allowed the runner to advance.
あのエラーがなければ試合の流れは変わっていただろう。
If not for that error, the course of the game would likely have been different.
記録上はエラーとして扱われたが、審判の判定は微妙だった。
Statistically it was marked as an error, but the umpire's call was questionable.