What does cb mean on a watch?

On a watch, "CB" typically stands for "Chronograph," which refers to a timepiece that includes a stopwatch function in addition to standard timekeeping. It can also refer to "Ceramic Bezel," indicating that the watch features a bezel made of ceramic material, known for its durability and scratch resistance. The specific meaning can vary based on the brand and model, so it's always good to check the manufacturer's specifications for clarification.