The word "watch" has several meanings, depending on its context.
1) A timepiece worn on one's wrist or attached to a lanyard, used for telling time and often featuring additional functions such as date display, stopwatch, or water resistance.
2) An act of observing something carefully over an extended period: "I will keep watch over the house while you are away."
3) A specific interval of time during which a task must be completed: "The security guard was on duty for his shift and had to stay awake through the entire watch."
4) An official inspection or examination, especially by a military unit: "They conducted a routine watch of their equipment."