witness
n. countablen. someone who sees an event happen, especially a crime or an accident. You might be asked to tell a court or the police what you saw.
n. a person who sees an event, typically a crime or accident, take place. Often used in legal contexts to refer to an individual who provides testimony under oath.
The witness told the police exactly what she saw.
Police are looking for a witness who saw the blue car leave the scene of the accident.
The prosecution called a surprise witness whose testimony directly contradicted the defendant's alibi for the night the crime was committed.
From Middle English witnesse, from Old English ġewitnes, equivalent to wit + -ness. Cognate with Middle Dutch wetenisse (“witness, testimony”), Old High German gewiznessi (“testimony”), Icelandic vitni (“witness”).
Commonly takes the preposition 'to' when describing the event seen ('a witness to the crime').