They sound almost identical, but they mean two very different things!

⏱️ CHRONOGRAPH = STOPWATCH
A watch with a function for measuring elapsed time.

🎯 CHRONOMETER = TESTED PRECISION
A watch or movement that meets specific accuracy standards, often verified through independent certification such as COSC.

And here's the surprising part:

A watch can be BOTH a chronograph and a chronometer!

Two words. Two meanings.