BackusNaur Form
en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form
Article
Backus–Naur form
Formalism to describe programming languages
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
In computer science, BNF (Backus Normal Form or BackusNaur Form) is one of the two main notation techniques for context-free grammars, often used to describe the syntax of languages used in computing, such as computer programming languages, document formats, instruction sets and communication protocol; the other main technique for writing context-free grammars is the van Wijngaarden form.