IMO that sounds horrible. Reminds me of the old clamshell plastic iBooks.... I don't know,

Book just has a very old-timey ring to me.
Which doesn't mean they won't do it. I also thought macOS Rincon would sound way cooler than Big Sur, but oh well I bet they have smarter people than me making such decisions ¯\_(ツ)_/¯
Following Apple's shift to California-themed names for its Mac operating systems with OS X Mavericks back in 2013, Apple appeared to take steps to protect a number of other California-related names by filing for trademarks under a series of shell companies intended to mask the true identity of...
www.macrumors.com