The word 遗嘱 (yízhǔ), meaning "will" or "testament", is formed by combining two conceptual characters: 遗, which carries the core idea of "leaving behind" (as in an inheritance or something bequeathed), and 嘱, which means "to instruct", "to enjoin", or "to give charge". Therefore, the compound naturally and intuitively conveys the complete concept of "instructions left behind", perfectly capturing the essence of a legal document that details the wishes of a deceased person.