expert witness

In one sentence

A person with specialized knowledge who testifies in court about technical or scientific matters beyond ordinary understanding.

Plain English

An expert witness is someone qualified by education, training, or experience to offer opinions on specialized subjects in court. Unlike regular witnesses who can only describe what they saw or heard, expert witnesses can interpret evidence and offer conclusions based on their expertise—for example, a forensic scientist explaining DNA results or a medical doctor discussing injuries. Both the prosecution and defense can call expert witnesses to support their cases. The opposing side has the right to challenge the expert's qualifications and cross-examine their opinions.

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Example

In a murder trial, the prosecution calls a forensic pathologist to explain the cause of death based on the autopsy findings. The defense then calls their own medical expert to challenge those conclusions. Both experts testify about technical matters that jurors couldn't understand without professional explanation.

Used in a sentence

“The expert witness testified that the defendant's fingerprints matched those found at the crime scene.”

Related terms

Circumstantial Evidence

Evidence that suggests guilt indirectly rather than proving it directly.

forensic evidence

Physical or scientific evidence collected and analyzed to establish facts in a criminal investigation or trial.

Mistrial

A trial that is declared invalid and must be restarted.

defendant

The person accused of a crime in a criminal case or sued in a civil case.

Stand Your Ground

A law allowing a person to use force, including deadly force, to defend themselves without a duty to retreat.

Castle Doctrine

A law stating that a person's home is their castle and they can use force to defend it without duty to retreat.

Expungement

A legal process that erases or seals a criminal conviction from your record.

Felony

A serious crime punishable by more than one year in prison or death.

This page is a plain-English reference and is not legal advice. Laws vary by jurisdiction and change over time. For specific situations consult a licensed attorney.