Alarm clock and Chronoscope

Alarm clock noun - A clock that wakes a sleeper at some preset time.

Chronoscope and alarm clock are semantically related In some cases you can use "Chronoscope" instead a noun phrase "Alarm clock".

Chronoscope noun - An instrument for accurate measurements of small intervals of time.

Alarm clock and chronoscope are semantically related in device that tells time topic. You can use "Alarm clock" instead a noun "Chronoscope".