Definition of clapboard (clapper (board) or slate)

a small black or white board or slate with a hinged stick on top that displays identifying information for each shot in a movie, and is filmed at the beginning of a take. The board typically contains the working title of the movie, the names of the director, the editor, and the director of photography, the scene and take numbers, the date, and the time. On the top of the clapboard is a hinged wooden stick (called a clapstick or clapper) which is often clapped to provide audio/visual synchronization of the sound with the picture during editing;electronic clappers and synchronization are currently in use instead of the old-fashioned clapboard.