A variable variable, used to refer to another Variable. Commonly used when discussing SourceCode in english when the speaker is refering to a variable and the name is unimportant.
The type of a MetaSyntacticVariable is generally held to be irrelavent, partly because there are commonly used variable names when the type is important (i, j and k for loop counters, for instance).
3 pages link to MetaSyntacticVariable: