Dear Colleague,

Good Day, it depends on what field of science you are talking about. I attached few articles you might find useful.

it means evaluating the theoretical achievements with experimental results.

Or when you do some experiments and evaluate the results.

Empirical means derived from observations. Something you measure/observe in a real experiment. Not theoretical evaluation. It might be a bit tricky with simulated datasets though. Some consider simulations as empirical evaluations, but some do not.