A silhouette is dark shadow, like a silhouette of a person standing under a street lamp, or a drawing that shows only the shape of an object.
A silhouette, pronounced "sil-ooh-ET," can be mysterious. After all, you can only see the shape of the person or object. So, it's fitting that the word's origin is a little mysterious, too. It was coined for Etienne de Silhouette, a French finance minister. One theory is that Silhouette decorated his chateau with the kind of dark outline drawings that now bear his name.