"Stereo headphones" refer to a type of headphones that can play sound from two different channels, creating a sense of depth and directionality in the audio. Full definition
A good pair of stereo headphones or a standard gaming headset will do. (pocket-lint.com)
It comes with an integrated audio jack so it can act as stereo headphones when connected to a music source such as a smartphone or an MP3 player. (geekwrapped.com)
Normal stereo headphones will use volume to help you determine where a sound is coming from, but virtual surround sound takes it even further. (howtogeek.com)