Indian Evidence Act, 1872
49. Opinion as to usage, tenets, etc., when relevant
When the Court has to
form an opinion as to-
the usages and tenets
of any body of men or family, the constitution and government of any religious or
charitable foundation, or
the meaning of words
or terms used in particular districts or by particular or by particular classes
of people, the opinions of persons having special means of knowledge thereon,
we relevant facts.