I found this description similar to your Italian source where 6 walls/quinte are mentioned...maybe it will help but I'm not sure if it's the exact equivalent translation of the term...maybe an architect out there could tell you if they correspond!

The main structure of the building is made up of six reinforced concrete bearing and shear walls, differently oriented and set back from the outer edge which is coated by curtain walls: continuous facade in glass and duralumin, separate from the structure, giving special lightness and allowing to see the modern open spaces inside.

The focus term is wing-walls
https://africaneditors.org/journal/IJPS/full-text-pdf/07061-...
https://sites.google.com/site/cabrillocollegeta9/_/rsrc/1321...
https://www.researchgate.net/profile/Alessandra_Pagliano/pub...
https://onlinelibrary.wiley.com/cms/asset/a4000c41-3e79-4b3a...
https://onlinelibrary.wiley.com/doi/full/10.1002/eqe.2890


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Note added at 22 hrs (2020-10-10 11:21:58 GMT)
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some references for "quinta"

"shear wing-wall"
https://www.google.com/search?q="shear wing-wall"&rlz=1C1CHB...

"concrete wing-wall"
https://www.google.com/search?rlz=1C1CHBF_itDO884DO884&sxsrf...

"seismic" "wing wall"
https://www.google.com/search?rlz=1C1CHBF_itDO884DO884&sxsrf...

"wing wall" "reinforcement"
https://www.google.com/search?rlz=1C1CHBF_itDO884DO884&sxsrf...

and so on

TRANSLATION
https://www.wordreference.com/enit/wing

"muro di quinta"
https://www.google.com/search?rlz=1C1CHBF_itDO884DO884&sxsrf...

"muro di ala"
https://www.google.com/search?rlz=1C1CHBF_itDO884DO884&sxsrf...

I think it is quite clear