Yes, these terms are often confused but mean different things. A Chronograph is a watch with a built-in stopwatch function (buttons to start, stop, and reset). A Chronometer is a specific certification given to a high-precision watch movement (usually mechanical) that has passed rigorous accuracy tests by COSC (Official Swiss Chronometer Testing Institute). A watch can be both, but "Chronograph" refers to the function, while "Chronometer" refers to the accuracy rating.