A witness is a person whose declaration under oath is received as evidence for any purpose, whether such declaration be made on oral examination, or by deposition or affidavit.
§ 1878.“Witness” defined
Title 2. Of the Kinds and Degrees of Evidence · Chapter 2. Witnesses · Enacted 1872 · no amendments on record · Last verified July 29, 2026
In one sentenceSection 1878 defines a witness as any person whose declaration made under oath is received as evidence, whether given through oral testimony, a deposition, or an affidavit.
Full Text of § 1878
Plain-English Summary
This single section opens Title 2's chapter on witnesses by fixing the term's meaning for the rest of the evidence provisions in this part of the code. A witness is a person whose sworn declaration is received as evidence for any purpose, and the definition is deliberately broad about the form that declaration takes.
It covers oral testimony given on examination, the same declaration recorded in a deposition, and a declaration made by affidavit. All three are treated as witness testimony under this definition, so the rules built around the concept of a witness reach a person regardless of which of these three forms carries the sworn statement.
Frequently Asked Questions
Who counts as a witness under Section 1878?
Any person whose declaration under oath is received as evidence, no matter the purpose it serves.
Does testimony have to be given live in court to count?
No. The definition covers oral examination, deposition testimony, and affidavits alike.
Is an unsworn statement covered by this definition?
No. The declaration must be made under oath to fall within the definition of a witness under this section.
Amendment History
(Enacted in 1872.)
Source & verification. Section text is reproduced verbatim from
the West's Annotated California Codes / Thomson Reuters. Enacted by the California Legislature.
Last verified July 29, 2026.
· Official source
Also known as: definition of witness california civil proceduresworn declaration evidence witness