A "stopped clock" refers to a clock that has stopped working and no longer keeps accurate time. Despite its inability to function properly, a stopped clock will still show the correct time twice a day. This phenomenon highlights the idea that even something that is broken can still be right occasionally. The phrase "stopped clock" is often used metaphorically to suggest that someone or something can be correct or valid at times, even if they are generally unreliable. This concept is commonly expressed in the saying, "Even a stopped clock is right twice a day," emphasizing the unpredictability of accuracy in various contexts.