Where does “sonet” come from?

sonet (Occitan) comes from Occitan son, from Latin sonus, from Latin sonō, from Proto-Italic *swonaō — to sound, resound.

Ancestry of “sonet”, step by step

Step	Language	Word	Meaning
1	Occitan	son	his; her; its; third-person plural present...
2	Latin	sonus	sound, noise; pitch; speech; tone, character,...
3	Latin	sonō	to sound, resound, make a sound or noise (and various sounds in-context)
4	Proto-Italic	*swonaō	to sound, resound