The Federal Rules of Evidence are a set of rules that govern the admissibility of evidence in federal court proceedings. The rules are designed to ensure that evidence presented in court is reliable and relevant to the case. They also provide guidance to lawyers and judges on how to handle evidence in a fair
From Wikipedia
First adopted in 1975, the Federal Rules of Evidence codify the evidence law that applies in United States federal courts. In addition, many states in the United States have either adopted the Federal Rules of Evidence, with or without local variations, or have revised their own evidence rules or codes to at least partially follow the federal rules.