Expert Witness

Business, Legal & Accounting Glossary

Definition: Expert Witness

What is the dictionary definition of Expert Witness?

Dictionary Definition

n. a person who is a specialist in a subject, often technical, who may present his/her expert opinion without having been a witness to any occurrence relating to the lawsuit or criminal case. It is an exception to the rule against giving an opinion in trial, provided that the expert is qualified by evidence of his/her expertise, training and special knowledge. If the expertise is challenged, the attorney for the party calling the “expert” must make a showing of the necessary background through questions in court, and the trial judge has discretion to qualify the witness or rule he/she is not an expert, or is an expert on limited subjects. Experts are usually paid handsomely for their services and may be asked by the opposition the amount they are receiving for their work on the case. In most jurisdictions, both sides must exchange the names and addresses of proposed experts to allow pre-trial depositions.

Full Definition of Expert Witness

An expert witness is the person who has the knowledge or competence to offer an opinion in court on a specific topic including information of a legal, scientific or medical nature. The expert witness may also perform other tasks for a litigator over the course of the case including testifying at the deposition and trial, evaluating cases and reviewing documents.

Generally, the first task of the expert witness is to review information about the details of the case. The expert witness may also be asked to evaluate the basic facts of the case, help the attorney understand complicated issues and outline an initial strategy. If the lawyer is reviewing a personal injury claim they may want the expert witness to examine medical information about the plaintiff to determine if the lawyer should take the case or not.

A common deliverable for an expert witness is an expert report which outlines their opinion about the case. Expert witnesses may also have to provide testimony under oath by for both attorneys. Finally, they will be asked to testify at trial, under oath, and will likely have to face cross-examination by opposing counsel.

Cite Term

To help you cite our definitions in your bibliography, here is the proper citation layout for the three major formatting styles, with all of the relevant information filled in.

Page URL
Modern Language Association (MLA):
Expert Witness. Payroll & Accounting Heaven Ltd. September 24, 2021
Chicago Manual of Style (CMS):
Expert Witness. Payroll & Accounting Heaven Ltd. (accessed: September 24, 2021).
American Psychological Association (APA):
Expert Witness. Retrieved September 24, 2021, from website:

Definition Sources

Definitions for Expert Witness are sourced/syndicated and enhanced from:

  • A Dictionary of Economics (Oxford Quick Reference)
  • Oxford Dictionary Of Accounting
  • Oxford Dictionary Of Business & Management

This glossary post was last updated: 28th April, 2020 | 3 Views.