preamble
n.n. the first part of a document or piece of software that explains the purpose or gives instructions. It is like the introduction that tells you what to expect.
n. the introductory section of a formal document, such as a constitution or a software license, that provides background or explains the purpose of the text. In computing, it often refers to the initial data or instructions that a program reads before executing the main code.
The preamble of the license explains why the software is free.
Before the main script runs, it checks the preamble to ensure the system requirements are met.
The preamble to the treaty establishes the foundational principles of international cooperation, while the subsequent articles provide the specific legal obligations for each signatory nation.
From Middle English preamble, from Old French preambule (French préambule), from Medieval Latin praeambulum, from praeambulō (“I walk before”).