The word "留念" is formed by combining the character "留", meaning to retain or keep, with "念", meaning to remember or think of. "留" is a pictophonetic character where "田" (field) serves as the semantic component suggesting permanence, and "卯" as the phonetic component. "念" is also pictophonetic, with "心" (heart) as the semantic component indicating mind or thought, and "今" as the phonetic component. Together, they create the meaning of keeping something as a memento or cherishing a memory.