Where does “五十鈴” come from?

五十鈴 (Japanese) comes from Japanese 鈴, from Middle Chinese 鈴.

Ancestry of “五十鈴”, step by step

Step	Language	Word	Meaning
1	Japanese	鈴	a bell, chime; Synonym of 駅鈴 : station bells...
2	Middle Chinese	鈴	—