刻骨銘心 [ㄎㄜˋ ㄍㄨˇ ㄇㄧㄥˊ ㄒㄧㄣ; ke4 gu3 ming2 xin1] lit. carved in bones and engraved in the heart (idiom) fig. etched in one's memory unforgettable ◄ ►