Where does “jonc” come from?

jonc (Middle Dutch) comes from Old Dutch jung, from Proto-West Germanic jung, from Proto-Germanic jungaz, from Proto-Germanic juwungaz, from Proto-Indo-European yuwn̥kós, from Proto-Indo-European h₂yuh₁en-, from Proto-Indo-European h₂ey- — vital force, life, age, eternity; day, morning.

jonc (Middle Dutch): young; most recent