SDIO Interface Type Definition


I've been experimenting with Arduino for a while now, and as I begin to venture into adding new components, I've noticed "SDIO" being used in a number of different contexts.

I've seen: "Secure Digital Input Output" "Serial Data Input Output" ... and others

Most of the posts I've read are related to interfacing Secure Digital cards for storage purposes. However, I'm particularly keen on the idea of implementing WiFi/BLE in my next project. There seems to be a great abundance of SPI capable modules, but I've noticed several that claim "SDIO" as the interface type which leads me to ask...

Is the SDIO interface, as it is used for modules such as these, even related to the SDIO which we rely on for SD card communication? If so, are they treated in a similar manner when it comes to the actual communication, each adhering to its own protocols? Or, are they just using the same pin configuration, and the similarities end there?

Thanks for any wisdom! Peter