Where does “cifer” come from?

cifer (Middle Dutch) comes from Medieval Latin cifra, from Arabic صِفْر, from Sanskrit शून्य, from Proto-Indo-European ḱówH-.

Ancestry of “cifer”, step by step

Step	Language	Word	Meaning
1	Medieval Latin	cifra	zero, numeral; numeral, cipher; zero
2	Arabic	صِفْر	zero, nothing, empty, void; nothing, cipher;...
3	Sanskrit	शून्य	zero; cipher, cypher; blank, deserted
4	Proto-Indo-European	ḱówH-	—