balloonian variable: n.

[Commodore users; perh. a deliberate phonetic mangling of boolean variable?] Any variable that doesn't actually hold or control state, but must nevertheless be declared, checked, or set. A typical balloonian variable started out as a flag attached to some environment feature that either became obsolete or was planned but never implemented. Compatibility concerns (or politics attached to same) may require that such a flag be treated as though it were live.