a human being

the collection of rules imposed by authority

be a witness to

a witness whose relationship to the opposing party is such that his or her testimony may be prejudiced against the opposing party

a witness who testifies under oath as to the good reputation of another person in the community where that person lives

a witness who has knowledge not normally possessed by the average person concerning the topic that he is to testify about

any witness who does not testify as an expert witness

a witness whose testimony is both relevant to the matter at issue and required in order to resolve the matter

the collection of rules imposed by authority