Hourglass and Stopwatch

Hourglass noun - A sandglass that runs for sixty minutes.

Stopwatch and hourglass are semantically related in timekeeping device topic. In some cases you can use "Stopwatch" instead a noun "Hourglass", when it comes to topics like device that tells time.

Stopwatch noun - A timepiece that can be started or stopped for exact timing (as of a race).

Hourglass and stopwatch are semantically related in timekeeping device topic. You can use "Hourglass" instead a noun "Stopwatch", if it concerns topics such as device that tells time.