In Simple terms :
Workspace One UEM -> Unified Endpoint Management :- To manage all endpoint devices from central location (For example -> Android, iPhone, W10)
Usual terms 
"Consolidate management silos across mobile devices, desktops (including Windows 10 and macOS), rugged devices and “things”. Reduce costs and improve security with real-time, over-the-air management across all use cases (including BYO).
Workspace One :- Used for Identity management :- Mainly for SSO
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