The lid, also called the top, is the wooden cover that is hinged to the spine and folds down to protect the interior of the piano when it is not being played. The front half of the lid is folded down when the lid is closed, and folded back when it is raised. The raised lid also serves as a reflecting surface for the sound waves that radiate from the soundboard. The waves come off the soundboard and are then reflected out towards the audience. When the lid is raised, it is held open by a wooden stick called the lid prop. Most lid props have a smaller stick called a half-prop, which can be used to keep the lid partially raised.
