A slate board with hinged clapping stick used in filmmaking to mark scenes, takes, and synchronize audio and video.
From 'clapper' (striking device) + 'board' (slate surface). Invented early in cinema to solve the problem of synchronizing separate audio and film recordings.
The distinctive 'clap' sound at the start of each film take was actually solving a technical problem—before digital syncing, editors matched the audio crack with the visual clap to align sound and picture perfectly.
Complete word intelligence in one call. Free tier — 50 lookups/day.