Microsoft is only making this change for the client-side Office Online apps. The Exchange Online, SharePoint Online, and Office Online server names will live on.
Microsoft's stated reason for the change: "Because our offerings have evolved to provide access to apps on more than one platform, it no longer makes sense to use any platform-specific sub-brands."
"We have already made these changes across most of our in-product experiences, communications, and marketing and technical content and expect to complete the remaining updates relatively soon," officials noted in a blog post on July 24.
I, myself, am no fan of Microsoft using "Word" to describe all flavors of Word, regardless of platform. To me, this complicates rather than simplifies, especially when a reader asks about a feature or problem which may be in one variant but not another. The way Microsoft often conflates Skype consumer and Skype for Business or OneDrive consumer and OneDrive for Business makes reading and writing about Microsoft products harder, not easier.
But I'm not part of the naming police at Microsoft; I'm just the messenger.
In Memoriam: All the consumer products Microsoft has killed off