witness

UK: /ˈwɪtnəs/ US: /ˈwɪtnɪs/ ,(wit′nis)

WordReference Random House Learner's Dictionary of American English © 2025

wit•ness /ˈwɪtnɪs/   v. [~ + object]

1. to see, hear, or know by personal presence and experience:
   to witness a crime.
2. to be present at and show this by writing one's signature:
   He witnessed her will.

n. 

3. a person who has witnessed something, esp. one who is able to declare what has taken place:
   [countable] a witness to the accident.
4. [countable] a person who gives testimony, as in a court of law.
5. something serving as evidence:
   [uncountable] His lined, gray face is witness to his suffering.

WordReference Random House Unabridged Dictionary of American English © 2025

wit•ness  (wit′nis), v.t. 

1. to see, hear, or know by personal presence and perception:
   to witness an accident.
2. to be present at (an occurrence) as a formal witness, spectator, bystander, etc.:
   She witnessed our wedding.
3. to bear witness to;
   testify to;
   give or afford evidence of.
4. to attest by one's signature:
   He witnessed her will.

v.i. 

5. to bear witness;
   testify;
   give or afford evidence.

n. 

6. an individual who, being present, personally sees or perceives a thing;
   a beholder, spectator, or eyewitness.
7. a person or thing that affords evidence.
8. a person who gives testimony, as in a court of law.
9. a person who signs a document attesting the genuineness of its execution.
10. testimony or evidence:
    to bear witness to her suffering.
11. (cap.) a member of the Jehovah's Witnesses.

• bef. 950; (noun, nominal) Middle English, Old English witnes origin, originally, knowledge, understanding; see wit¹, -ness; (verb, verbal) Middle English, derivative of the noun, nominal

wit′ness•a•ble, adj. 
wit′ness•er, n. 
Synonyms

• 1. perceive, watch, mark, notice, note. See observe. 
• 10. proof, confirmation, substantiation.

Collins Concise English Dictionary © HarperCollins Publishers::

witness / ˈwɪtnɪs/ noun

1. a person who has seen or can give first-hand evidence of some event
2. a person or thing giving or serving as evidence
3. a person who testifies, esp in a court of law, to events or facts within his or her own knowledge
4. a person who attests to the genuineness of a document, signature, etc, by adding his or her own signature
5. bear witness ⇒ to give written or oral testimony
6. to be evidence or proof of
   Related adjective(s): testimonial

verb

1. (transitive) to see, be present at, or know at first hand
2. to give or serve as evidence (of)
3. (transitive) to be the scene or setting of: this field has witnessed a battle
4. (intransitive) to testify, esp in a court of law, to events within one's own knowledge
5. (transitive) to attest to the genuineness of (a document, signature, etc) by adding one's own signature

Etymology: Old English witnes (meaning both testimony and witness), from witan to know, wit² + -ness; related to Old Norse vitni

ˈwitnessable adjective

ˈwitnesser noun