The word "阑珊" is formed by combining the character "阑", which historically denotes a door frame or barrier and extends to meanings like late or fading, with "珊", which in this compound loses its independent sense and instead phonetically complements "阑" to create a disyllabic expression. Together, they function as a single lexical unit where the characters are fused, primarily conveying the meaning of decline, waning, or diminishment, as in fading light or diminishing energy.