The ``HYPeR"-sign refers to the "Hyper Generic RPG". The word ``hyper'' has no special meaning, unless you compare it something like a ``hyper-space'', which is ``above'' the normal ``space''. A HYPeR -sign in a document shows that it is compatible with the whole HYPeR-system.
The LATEX-command for the HYPeR-sign is