It's something that protects the recording once it's made, too.
So what is it? Well, a phonogram is a written-down version of a sound. It's not the sound itself, it's just the written-down sign or signs that represent it.
This can be a syllable, a sound, or a word, though quite often when people say phonogram they mean string of letters with the same sound (as in [c]at, [m]at, [s]at, [gn]at).
The legal meaning of phonogram is a bit different, because here phonogram means audio recording.
The international copyright sign for audio recordings is a circled capital letter P, like this: ℗, where the P stands for phonogram.
This means that any pongy perisher who pinches or publishes a piece with a ℗ on it is a poxy pirate.
Word To Use Today: phonogram. This word comes from the Greek phōnē, sound or voice, and gramma, line.