Testimony provided by one who is recognized by the court in a particular field relevant to the evidence at hand.

Testimony given in relation to some scientific, technical or professional matter by experts, i.e., person qualified to speak authoritatively by reason of their special training, skill or familiarity with the subject.

"n. opinions stated during trial or deposition (testimony under oath before trial) by a specialist qualified as an expert on a subject relevant to a lawsuit or a criminal case. See also: expert witness "