1. Introduction

Approximately 212 RFCs, or about 7% of RFCs issued so far, starting with [RFC269], contain the terms `foo', `bar', or `foobar' used as a metasyntactic variable without any proper explanation or definition. This may seem trivial, but a number of newcomers, especially if English is not their native language, have had problems in understanding the origin of those terms. This document rectifies that deficiency.

Section 2 below describes the definition and etymology of these words and Section 3 interprets them as acronyms.

As an Appendix, we include a table of RFC occurrences of these words as metasyntactic variables.