The experience of that failure was engraved deeply in his heart.

engraved 是动词 engrave 的过去分词形式。engrave 由前缀 en-（表示"使进入某种状态"）和 grave（"雕刻"）组成，字面意思是"使被雕刻"。在句中表示"被铭刻"的状态，引申为"深深铭记"的意思。