Wikipedia
The Guitolão is a chordophone exclusively designed by one of the masters of Portuguese guitars making, the luthier Gilberto Grácio. He started to develop the prototype instrument, originally built for Carlos Paredes in 2001, and only 3 types were made. The term Guitolão, is a match from the lexical between Portuguese Guitar and Violão (Guit + olão). Although, there are some connoisseurs who have tried to undo this neologism, but the use of the term makes sense because the initial idea was to create an instrument similar to a Portuguese guitar, but without the need of an accompaniment instrument (typical from the famous Portuguese musical genre, Fado). So while this is not the most correct terminology, however, is the one that makes more sense.
After a long process of calibration and calculation of the length of the vibrating strings to have the correct measurement, allowing a perfect pitch, this instrument becomes a balanced soloist guitar type, with huge richness in harmonics, largely due to the increased length of the string (from the bridge to the nut are 24,4 inch). Another important aspect is the dynamic response from the 12th fret of this instrument, that the normal Portuguese guitar does not retain.