「以後」 (Igo) means "after that," "from now on," or "hereafter." It refers to a point in time from now or a specific past event onward. It implies a continuing period. For example: 今日以後、このルールを守ってください。(Please observe this rule from today onwards.)

ある時よりも後のことです。未来を表します。例：今日以後。