expression, adverb
accidentally; by mistake; in error
Adverbial て-form used before a verb to say that an action happened unintentionally or because of an error. Often has a slightly formal or written feel compared with 間違って or うっかり.
誤って古いファイルを削除してしまった。
I accidentally deleted the old file.
彼は誤って別の電車に乗った。
He got on the wrong train by mistake.
Grammatically the て-form of 誤る, meaning to make a mistake or err. The kanji 誤 is conventionally associated with error or mistaken action; the alternate 過って spelling is rare.