i have seen readers advertised as wiegand with usb plugs.
The term wiegand is sometimes missuses to indicate the type of card. Of course there is a real wiegand card but they are so old and rare as to be not a form of confusion. Other forms of RFID card can be encoded in a wiegand format and I guess that is what is meant here.
Wiegand is an output format with two signals, one pulsing when there is a logic one in the code and the other pulsed when there is a zero.
The readers I designed could be set to give a serial output, wiegand output and even a bar code output all from the one type of card.