Since many major software suites are slowly moving to an online-only approach, it is not a big surprise that Microsoft has decided to rename its Office Online suite by removing the "Online" part. However, the branding change does not apply to the following server products: Exchange Online, SharePoint Online, Project Online, and Office Online Server.
https://www.notebookcheck.net/Microsoft-drops-the-Online-from-Office-Online.428199.0.html