##What does prima facie mean?
~ Portland, OR
This is a latin expression that is usually used to mean a rebuttable presumption. So, Prima Facie is used by lawyers to describe who presents evidence when. After a prima facie showing of evidence, the burden shifts to the other party to show their evidence.
Sometimes with a rebuttable presumption, the person receiving the legal benefit of the presumption does not have to show substantial evidence first, they just have to make a minimum showing of evidence. So, the adverse party must show evidence to disprove (or rebut) the rebuttable presumption. As such, a prima facie showing of evidence is usually a necessary and valuable step in a legal proceeding.
For example, in patent law, an issued patent is considered prima facie valid. So, first the patent holder presents the certified patent grant to the court. Then the alleged patent infringer has the burden to prove that the patent is invalid. This is one of the primary benefits of receiving a patent grant: the presumption of validity of the patent.
Similarly, in trademark law, a trademark registration certificate is prima facie valid, and, it is up to the trademark infringer to show that the trademark is invalid.
You can find lots of legal terms in Cornell's WEX (community built law dictionary and encyclopedia), here is a link to Prima Facie.