Hi sbron8,
Thanks for posting in our forum. As far as I know, Microsoft Outlook is an email client and Exchange is a Microsoft proprietary email server and calendar server.
Outlook is part of the Microsoft Office suite of software and programs which allow you to manage your emails, contacts, address book, tasks, calendar, all in one place.
Here is an article about Outlook for your reference: https://support.office.com/en-ie/article/video-what-is-outlook-10f1fa35-f33a-4cb7-838c-a7f3e6228b20
Microsoft Exchange Online is a hosted messaging solution that delivers the capabilities of Microsoft Exchange Server as a cloud-based service. It gives users access to email, calendar, contacts, and tasks from PCs, the web, and mobile devices.
For more detailed information about Exchange online, you can refer to this article: https://docs.microsoft.com/en-us/office365/servicedescriptions/exchange-online-service-description/exchange-online-service-description
Hope it can be helpful.
Best Regards,
Huni