Noun
chess clock (plural chess clocks)
A device consisting of two clocks and a switch for running one at a time, used in chess and other games to measure how much time each player takes.
A chess clock that was patented in 1975 was developed by Joseph Meshi and became the first commercially available digital chess clock. Source: Internet
Analog game clocks A typical analog chess clock Analog clocks are equipped with a "flag" (a Dutch invention) that falls to indicate the exact moment the player's time has expired. Source: Internet
Before the start of the game, either the arbiter decides, or whomever is playing Black, where the chess clock is placed. Source: Internet