Definitions

1. noun

A symbol or character used in a metasyntax, such as a markup language or a programming language, to represent or denote a concept or rule.

“The use of angle brackets in XML is an example of a metasymbol.”

2. noun

A symbol or character that is used to represent or denote a metasyntax concept or rule in a language or notation system.

“The asterisk is often used as a metasymbol in regular expressions.”