preamble (n.)

"prologue, preface, preliminary statement," late 14c., from Old French preambule (13c.) and directly from Medieval Latin preambulum, neuter adjective used as a noun, properly "preliminary," from Late Latin praeambulus "walking before," from Latin prae "before" (see pre-) + ambulare "to walk" (see amble (v.)). Especially the introductory paragraph of a statute or resolution, stating the reason for and intent of what follows. Related: Preambulary.