In 1974 I heard Stephen P. Hubbell state in front of an audience that "...evolution is the single most thoroughly documented fact known to man." Given what we have learned since then his statement is probably still true. The theorists are still behind the research curve. "Fact" is a layman's word, and nothing by way of rigorous proof is implied by it. Newton's laws of Gravity are "facts", and heavily relied on, dispite their technical disproof by the perihilion of mercury experiment.
Of course. The facts are mere observations or raw data. The scientist requires verification of his facts and repeatability. Newton's description of gravity is perfectly acceptable to the defender of a keep who is busy dropping rocks on an attacker's head.