Latin for "at first sight." Prima facie may be used as an adjective meaning "sufficient to establish a fact or raise a presumption unless disproved or rebutted;" e.g., prima facie evidence. It may also be used as an adverb meaning "on first appearance but subject to further evidence or information;" e.g., the agreement is prima facie valid.
A prima facie case is the establishment of a legally required rebuttable presumption. It is generally understood as a flexible evidentiary standard that measures the effect of evidence as meeting, or tending to meet, the proponent's burden of proof on a given issue. In that sense, a prima facie case is a cause of action or defense that is sufficiently established by a party's evidence to justify a verdict in his or her favor, provided such evidence is not rebutted by the other party.