Do you know why Windows Vista named "Vista"? The name originates from "VI", which means "six" in roman number. Therefore "Windows Vista" means "Windows 6". I think that Windows 8.1 is originally "8+1", which means "Windows 9".
I thought that Vista was from "VI (6)" because Vista was not a codename. Its codename is Longhorn. Windows and Codename Win 3.1x: Janus Win NT 3.1: Razzle Win NT 3.5x: Daytona Win 95: Chicago Win NT 4: Cairo Win 98: Memphis Win 2000: NT 5.0 Win Me: Millennium (the same as product name) Win XP, 2003: Whistler Win Vista, 2008: Longhorn Win 7, 2008 R2: Seven (the same as product name) Win 8, 2012: Eight (the same as product name) Win 8.1, 2012 R2: Blue Win 10, 2016, 2019, 2022: Threshold/Redstone/... Win 11: Sun Valley
The word Vista represents a pleasing view, and since Windows Vista came right after Windows XP, I think they wanted to express the alluring GUI of the OS. No. It uses a minor version number. Windows 8 (8.0) is the OS while 8.1 is the revised version of it.
Vista is just the Italian word for sight / view (and by extension means Outlook / Panorama) Speaking about Italian words used in IT I'm not sure how many English speaking people got the joke behind the name Nvidia. It's a joke on the Italian word "Invidia" which means literally "Envy" and the word video (which works both in Italian and English), obviously refereed to competitors.
Spanish is very similar to Italian being both neo-Latin languages (like Portuguese, French, Romanian...). "The view from here is stunning" becomes La vista da qui è impressionante (in Italian) La vista desde aquí es impresionante. (in Spanish) A vista daqui é impressionante (in Portuguese)