The situation you described is an example of support for a scientific claim. When multiple scientists perform the same experiment under similar conditions and obtain consistent results, it lends support to the conclusion that water boils at 100°C at standard atmospheric pressure.
If the results were consistently replicated, it strengthens the reliability of the claim, but it does not necessarily constitute a theory or proof. A theory is a well-substantiated explanation of an aspect of the natural world that is based on a body of evidence, while proof is a term more commonly associated with mathematics and logic rather than empirical science. In this case, the repeated experiments provide support for the claim regarding the boiling point of water.