noun. A serious mistake.

noun. A metasyntactic variable name, a place holder for words; compare foo, bar.

"I thought this was pretty cool treguly@ns: ~$ host - t txt foobar. wp.dg.cx descriptive text "The term foobar is a common placeholder name, also referred to as metasyntactic variable, used in computer programming or computer-related documentation."

Adar  Aer  Afar  Ajar  Ar