Where does “кана” come from?

кана (Russian) comes from Japanese 仮名, from Japanese 名, from Middle Chinese 名 — name.

кана (Russian): kana

Definitions

Step	Language	Word	Meaning
1	Japanese	仮名	a category of Japanese syllabary scripts: kana; a...
2	Japanese	名	name; reputation; famous, great, noted
3	Middle Chinese	名	name

кана — Etymology, Origin & Word History | Etymology Explorer