The Japanese noun 'オーケー (おーけー)' is a loanword derived from the English word 'okay'. It is commonly used in casual conversations to express agreement, acceptance, or acknowledgment. It can also be used to indicate that something is satisfactory or acceptable. For example: Is it okay if I leave early?「早く帰ってもオーケー?」(はやくかえってもおーけー?). The plan is okay「そのプランはオーケーだ」(そのぷらんはおーけーだ). Note that 'オーケー' is often written in katakana to emphasize its foreign origin and is used in informal settings.