The word **牢记 (láojì)** is a compound formed by combining the character **牢 (láo)**, which originally means "firm," "secure," or "prison" (conveying a sense of being tightly bound or unshakable), with the character **记 (jì)**, which means "to remember" or "record." Together, they create a verb meaning "to firmly remember" or "to keep deeply in mind," where **牢** acts as an adverbial intensifier, metaphorically suggesting that the memory is solid, secure, and not easily forgotten.