a preliminary statement in a book by the book's author or editor, setting forth its purpose and scope, expressing acknowledgment of assistance from others, etc.
2.
an introductory part, as of a speech.
3.
something preliminary or introductory: The meeting was the preface to an alliance.
4.
Ecclesiastical. a prayer of thanksgiving, the introduction to the canon of the Mass, ending with the Sanctus.
–verb (used with object)
5.
to provide with or introduce by a preface.
6.
to serve as a preface to.
Origin: 1350–1400; ME < MF < ML prēfātia, for L praefātiō a saying beforehand, equiv. to praefāt(us) (ptp. of praefārī to say beforehand; see pre-, fate) + -iōn--ion
A preliminary statement or essay introducing a book that explains its scope, intention, or background and is usually written by the author.
An introductory section, as of a speech.
Something introductory; a preliminary: An informal brunch served as a preface to the three-day conference.
often Preface The words introducing the central part of the Eucharist in several Christian churches.
tr.v.
pref·aced, pref·ac·ing, pref·ac·es
To introduce by or provide with a preliminary statement or essay.
To serve as an introduction to.
[Middle English, from Old French, from Latin praefātiō, praefātiōn-, from praefātus, past participle of praefārī, to say before : prae-, pre- + fārī, to speak; see bhā-2 in Indo-European roots.] pref'ac·er n.
[pref-is] 
noun, verb, -aced, -ac⋅ing.
ɪs