What is 'Microsoft 365'? What happened to 'Office 365'?

The term “Office 365” has changed meaning over time, so confusion is understandable. “Microsoft 365” is relatively recent and now overlaps with “Office 365”. Here’s what each term means now and a short history of how we got here.

What is “Microsoft 365”?

“Microsoft 365” is the broad label for the many “subscription” plans that Microsoft sells their combination software and services under.

Consumer Microsoft plans like Microsoft 365 Family or Microsoft 365 Personal then Business plans like Microsoft 365 Business Basic through to the alphanumeric soup of Enterprise plans (E5, F3, G5 etc).

Microsoft itself talks about “Microsoft 365 with Office apps”, separating the Office apps (Word, Excel, PowerPoint etc) from “Microsoft 365” plans. Not all Microsoft 365 plans include access to the Office apps, though most do.

What is “Office 365”?

“Office 365” started life as a branding name for the annual payment or subscription model. Only five years ago, you bought an Office 365 plan which included (then) Office 2016 software. ‘Office 365’ as a consumer product has been sold since 2013 (for Office 2013).

In 2018 there was a gradual change from calling the software “Office 2016” to “Office 365” the splash screen when starting a program was the first sign of the change.

Outlook 2016 splash screen in 2018, starting the change to “Office 365” naming for software.

But calling the software “Office 365” didn’t last long. Just a year later, “Office 365” software became “Microsoft 365”, again informally announced via the splash screens.

In 2019 Word switches from “Office 365” to “Microsoft 365” naming.

These days the individual apps are named according to their platform then ‘… Microsoft 365’, for example “Word for Mac for Microsoft 365” or “Excel for Microsoft 365” (‘Windows’ is implied in Microsoft’s world).

In today’s strict Microsoft speak, “Office 365” doesn’t mean anything. But the name is still used in many places, perhaps by accident, like the title for the https://office.com home page “Office 365 login | Microsoft Office”.

Office.com home page in mid-November 2021 using the title ‘Office 365’.

“Microsoft 365 ≈ “Office 365”

Out in the real world, beyond the Redmond group-think bubble, the terms “Microsoft 365” and “Office 365” are mostly used interchangeably. The two are almost equal “≈” in the world.

There are no hard rules about this. We tend to talk about “Office 365” when referring to the software alone leaving “Microsoft 365” for mentions of the plans like Personal/Family etc.

What about Office 2021 and Office 2019?

The word “Office’ followed by a year means the perpetual license, single payment, Microsoft Office software e.g. Office 2021, Office 2019, Office 2016 etc.

There’s also “Office LTSC”, the enterprise version of Office 2021.

Four signs that Office 365 will become Microsoft 365
All about Office 2021 for Windows & Mac
Office LTSC 2021 explained, the good and bad

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