What is the math definition of experimental?

The Word "experimental" is usually used to describe data that have come from an actual test or experiment. These data are opposite to "theoretical" data, which are only educated guesses at what the data should look like.

In statistics, theoretical probability is used a lot. For example, if I flip a coin, in theory, it would land on each side half of the time. Perform some trials, however, and this percentage may be skewed. The experimental data that you collect probably wouldn't exactly match the theoretical probability.