Yes, he meant AREF. What he is showing there is the board plugged direct into the Arduino's header, but the VIN of the Lepton board connects to AREF not a voltage pin. By connecting your supply voltage (5V) direct to that AREF pin you are then able to provide power to the Lepton board, and it has no noticeable effect on the Arduino since connecting 5V to AREF is a perfectly valid thing to do (though pretty pointless).
AREF and VREF are both pretty much interchangeable. Analog REFerence, and Voltage REFerence. It could be said that one is the Analog voltage REFerence, and the other is the Voltage REFerence for analog. Some chips call it AREF and some VREF. Some even provide VREF+ and VREF- or AREF+ and AREF- depending on the complexity of the ADC in the chip.