a short introductory essay preceding the text of a book
source: WordNet 3.0
Something spoken as introductory to a discourse, or written as introductory to a book or essay; a proem; an introduction, or series of preliminary remarks.
source: Webster 1913
verb
furnish with a preface or introduction
She always precedes her lectures with a joke. He prefaced his lecture with a critical remark about the institution.
source: WordNet 3.0
To introduce by a preface; to give a preface to; as, to preface a book discourse.