incipit
nounThe opening words of a text, especially when used in place of a title to identify an otherwise untitled work.
‘(Here) beginneth’: the first word in a preliminary formula common in medieval manuscripts and early printed books, introducing the title or name of the work or of the preface or other part of it: as, “Incipit preambulum”; “Incipit prologus in libellum qui dicitur Promptorius Parvulorum,” etc. Compare
The introductory words of a book or section of a book. Compare
The first few words of a text, especially its first line.