[Buddha-l] Pali Canon: Nibbana as Nameless

[Gruenig, Hans Werner]

I recall reading at least one sutta in which the Buddha indicates that nibbana can't be described.  

According to the PTS Dictionary, "Nibbana is the untranslatable expression of the Unspeakable, of that for which in the Buddha's own saying there is no word, which cannot be grasped in terms of reasoning and cool logic, the Nameless, Undefinable."  

Does anyone know where such discussions occur in the suttas?

Thank you,
-Hans.