What is the common name for the IEEE 802.11b wireless LAN?

The IEEE 802.11b wireless LAN standard is commonly known as WiFi. This designation arose from the Wireless Fidelity branding, which was developed to promote interoperability among devices that utilize this standard for wireless connections. WiFi allows for wireless data transfer at speeds of up to 11 Mbps, operating in the 2.4 GHz frequency band.

While other terms like WiMax, Ethernet, and Bluetooth are associated with different technologies—WiMax pertains to a different broadband wireless standard, Ethernet refers to a wired networking standard, and Bluetooth is used for short-range wireless communication—none of these are interchangeable with WiFi. WiFi's widespread adoption and association with wireless internet access make it the correct answer to this question.