I've seen both the terms Enhanced Key Usage and Extended Key Usage, and both were abbreviated as EKU. Do both refer to the same extension or property?
The correct name for the standard extension is Extended Key Usage; see section 188.8.131.52 of RFC 5280. Its OID is 184.108.40.206.
Confusion comes from Microsoft documentation and software:
Since Microsoft-specific extensions are Microsoft-specific, Microsoft's CA ("Certificate Services") usually includes both extensions (the standard one and the Microsoft one) in issued certificates.