For other uses, see Clock (disambiguation).
"Timepiece" redirects here. For the Kenny Rogers album, see Timepiece (album). For the 1965 short film by Jim Henson, see Time Piece.
A clock is an instrument to indicate, keep, and co-ordinate time. The word clock is derived ultimately (via Dutch, Northern French, andMedieval Latin) from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a striking mechanism has traditionally been known as a timepiece.