Used to refer vaguely to something already mentioned or understood from context, often when summarizing or avoiding repetition.
He said he was late for such and such reasons.
Due to various circumstances, I'll take the day off today.
Rare kanji spelling; mainly encountered in older or formal writing.
Reduplication of the classical demonstrative かく (thus, in this way). The exact historical derivation is uncertain, but it has been used since classical Japanese to refer vaguely to previously mentioned matters.