Audio Stream Input/Output

Audio Stream Input/Output (ASIO) is a computer audio interface driver protocol for digital audio specified by Steinberg, providing high data throughput, synchronization, and low latency between a software application and a computer's audio interface or sound card. ASIO bypasses the normal audio path from a user application through layers of intermediary operating system software, such as KMixer, Direct KS or WASAPI, so that an application connects directly to the sound card hardware.

Source: Wikipedia — Audio Stream Input/Output (CC BY-SA 4.0)