Quadriphonic is a term that is commonly used to describe sound systems with four channels of audio. There are many synonyms for quadriphonic, including four-channel, four-track, and four-way sound. Some other common synonyms for quadriphonic include stereophonic, surround sound, and multichannel sound. These terms all refer to sound systems that use multiple channels to create a more immersive audio experience. While quadriphonic was a popular term in the 1970s, it has largely been replaced by more modern terms like surround sound and multichannel sound. However, the basic concept of using multiple channels to create a more immersive audio experience remains unchanged.