Technically speaking, Bluetooth is wireless since it isn’t wired.

In terms of product labeling and marketing though, something called ‘wireless’ (with no mention of Bluetooth) is most likely using a wireless dongle of some sort. 

• Wireless keyboards that connect to a USB receiver, can only connect to a computer via a USB port.
• Bluetooth connectivity does not require a receiver, and can connect to a Bluetooth-enabled device without any ports.

There are a few general advantages to USB Dongle:

• It will work with any device that can take the dongle (in this case, anything with a USB   port). That is to say, devices that have USB but not Bluetooth can use this.
• Generally, you can get a higher polling rate and/or use less power.
• The pairing process tends to be a lot simpler- usually you just plug it in and turn the device on.
• Devices that use this tech are generally cheaper.

Bluetooth has the advantage that it can be paired with anything that has Bluetooth support (which is most mobile devices these days) and does not need any additional hardware. As a corollary to this, you don’t use up a USB port with the dongle. For some devices that have very few ports, this can be a pretty major plus.