Here’s a good reference of what the actual deliverables are for Office 365. The terms can get confusing, especially when trying to understand the Office 365 Pro Plus and the desktop suite.

•Office 365 Platform includes information about the Office 365 hosted solution platform that is common across the other services. The Office 365 Platform service description is where you’ll find details about Office 365 user management, support, service updates, privacy and security policies, and other operational details that apply across the individual services and are part of the core Office 365 service.

•Exchange Online is a hosted messaging service offered in some Office 365 plans that web-based email, calendar, contacts, and tasks from PCs, the web, and mobile devices. In the Exchange Online service description, you can easily see which Exchange features are available across Office 365 plans. In addition, you can compare Exchange Online feature availability to an Exchange [...]