The literal translation of binaural is 'of two ears'. It is a word associated with hearing and recording.
Binaural hearing is what allows humans and other animals to pinpoint the source location of a sound. Every human and animal has a uniquely shaped ear. The shape of our ears and the related HRTF (Head Related Transfer Function) produce a very specific signature for any given sound. The circumference of our heads, the material of clothing we wear, the distance from the sound source, the shape and composition of materials around us also help form the sounds we hear every day.
Binaural recording involves capturing sound using a stereo binaural microphone that is shaped and configured like two human ears. A binaural microphone is a special stereo microphone that contains two prosthetic, human-shaped ears with microphone capsules embedded inside each ear canal. Binaural microphones capture audio the same way your real ears hear sounds. Incoming sound waves are changed by the ear-shaped pinna of the microphone, just like your ears would shape the incoming sound waves. Our brains understand these changes as directional cues. When you listen to binaural recordings using headphones, the result is a natural three-dimensional sound that gives the listener the sensation of being in the space where the audio was recorded as well as the sensation of facing the same direction as the microphone was during the recording.