The term "rosebud" refers to a small, tightly closed bud on a rose plant. It is often used metaphorically or symbolically in literature and film to represent innocence, purity, hope, love, or nostalgia. In the 1941 movie "Citizen Kane," directed by Orson Welles, the last scene shows a sled with the name "Rosebud" on it as the protagonist's final word before dying. The term has since become synonymous with the idea of discovering one's deepest secret or uncovering hidden truths.