If you know that the prefix chrono- means having to do with time what can infer a chronometer is?

If you know that the prefix "chrono-" means having to do with time, you can infer that a chronometer is a device that measures time.

Here's how:

* chrono- = time

* -meter = a device that measures something

Therefore, a chronometer is a time-measuring device, like a very precise clock or watch.