Final answer:
The 16-bit field in the Ethernet frame that allows for use with multiple protocols like IPv4 or IPv6 is known as the Ethernet Type field, indicating which protocol's data is being carried.
Step-by-step explanation:
The 16-bit field referred to in the Ethernet frame context is the Ethernet Type field. This field is crucial because it outlines which protocol is encapsulated within the frame, allowing for the differentiation between multiple protocols such as IPv4 or IPv6. The Ethernet frame serves as a container that can carry data for various network protocols, and by inspecting the Ethernet Type field, network devices know how to process the payload of the frame accordingly.