An audio format is a medium for sound recording and reproduction. The term is applied to both the physical recording media and the recording formats of the audio content—in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to store the data. Note on the use of analog compared to digital in this list; the definition of digital used here for early formats is that which is represented using discrete values rather than fluctuating variables. A piano roll is digital as it has discrete values, that being a hole for each key, unlike a phonograph record which is analog with a fluctuating groove.

Phonograph cylinders are the earliest commercial medium for recording and reproducing sound. Commonly known simply as "records" in their heyday, a name which has been passed on to their disc-shaped successor, these hollow cylindrical objects have an audio recording engraved on the outside surface which can be reproduced when they are played on a mechanical cylinder phonograph. The first cylinders were wrapped with tin foil but the improved version made of wax was created a decade later, after which they were commercialized. In the 1910s, the competing disc record system triumphed in the marketplace to become the dominant commercial audio medium.