What is field recording?

Field recording is the term used for an audio recording produced outside a recording studio, and the term applies to recordings of both natural and human-produced sounds. It also applies to sound recordings like electromagnetic fields or vibrations using different microphones like a passive magnetic antenna for electromagnetic recordings or contact microphones. For underwater field recordings, a field recordist uses hydrophones to capture the sounds and/or movements of whales, or other aquatic organisms. These recordings are very useful for sound designers. - Wikipedia