Broadly, any metalanguage is language or symbols used when language itself is being discussed or examined. In logic and linguistics, a metalanguage is a language used to make statements about statements in another language (the object language). Expressions in a metalanguage are often distinguished from those in an object language by the use of italics, quotation marks, or writing on a separate line.
Read more about Metalanguage: Types of Metalanguage, Types of Expressions in A Metalanguage, Role in Metaphor, Role in Computing