There is no agreement as to which word in Polish dictionary is the longest, but our orthographic rules allow for such structures as:

ponaddziewięćtysięcydziewięćsetdziewięćdziesięciodziewięciokilometrowy

which means "longer than 9999 kilometers". You could make this word infinitely longer by adding more kilometers, this is just an example.

Of course, you won't find words like this in any dictionary, and, besides, there is no need to use words that are so long, but nevertheless it's theoretically possible and gramatically correct ;)

Hi Nanie,

in Italian the longest word found on a dictionary is "Precipitevolissimevolmente", which means "very quickly" and is used mainly as a funny word.

Here is the link to the online dictionary for this entry:

http://www.treccani.it/vocabolario/precipitevolissimevolmente/

Bye,

Corrado