preface

Short definition from Wiktionary

Noun

1. 1
   A beginning or introductory portion that comes before the main text of a document or book, typically serving to contextualize or explain the writing of the book and sometimes to acknowledge others' contributions; especially, such a discussion written by the work's own author.
2. 2
   An introduction, or series of preliminary remarks.
3. 3
   A variable prayer forming the prelude or introduction to the Eucharistic Prayer or canon of the Mass, following the Sursum corda dialogue and leading into the Sanctus.
4. 4
   A title or epithet.
5. 5
   Alternative letter-case form of preface (“prayer before the canon of the Mass”).

Verb

1. 1
   To introduce or make a comment before (the main point); to premise.
2. 2
   To give a preface to.