No. Microsoft 365 (previously office 365) is not a web app. They have web apps, and some licenses (the bare bones $6/mo one) only has web apps. But overall the suite of apps can’t be defined as web based.

Not to be confusing, but some of the apps are only web apps, but those are “other” apps than you’re probably thinking of. Like Planner or Power Automate. The “office” apps like outlook, word, excel and PowerPoint all have desktop and web versions included.

Office no longer exists as it used to. The applications are being turned into offline websites. See Modern Outlook, Modern Teams ect. They are cost cutting all the different app platforms down to one. An offline website for each app.

peak enshitification

There’s Office online, which has a free tier and a “365” tier, whatever that means. Does it mean that you have Office available 365 days a year? Good luck on February 29th, I guess. /j

Anyway, Microsoft transitioned Office into a subscription-based model, which I abhor because I just want to have a piece of software without feature updates, just bug and security fixes. So Office 365 is just normal Office, but on a subscription basis.