Where does “kirjainsana” come from?

kirjainsana (Finnish) comes from Finnish sana, from Finnish luokka, from Finnish luokki, from Proto-Slavic lǫkъ, from Proto-Balto-Slavic *lankás, from Proto-Indo-European lenk- — to bend.

kirjainsana (Finnish): acronym

Definitions

acronym

Ancestry of “kirjainsana”, step by step

kirjainsana traces back through two separate lines of ancestry.

via Finnish sana

Step	Language	Word	Meaning
1	Finnish	sana	word; Word, Scripture; lesson
2	Finnish	luokka	class; class, social class; grade
3	Finnish	luokki	shaft bow
4	Proto-Slavic	lǫkъ	bow
5	Proto-Balto-Slavic	*lankás	bow
6	Proto-Indo-European	lenk-	to bend

via Finnish kirjain

Step	Language	Word	Meaning
1	Finnish	kirjain	letter; Genitive plural form of kirja
2	Finnish	kirjata	to book, log, register; to register
3	Finnish	kirja	book; quire
4	Proto-Finnic	kirja	decoration, carving, pattern

Every word from Proto-Indo-European lenk- →Every word from Proto-Balto-Slavic *lankás →Every word from Proto-Slavic lǫkъ →