apostolicity|əˌpɒstəˈlɪsɪtɪ| [a. Fr.apostolicité: see apostolic and -ity.] The quality of being apostolic in character or origin. 1832G. Faber (title) The Apostolicity of Trinitarianism.1855I. Taylor Restor. Belief (1856) 120 Good anchor-hold in the roadstead of apostolicity.