Where does “osmiúhelník” come from?

osmiúhelník (Czech) comes from Czech osm, from Old Czech osm, from Proto-Slavic osmь, from Proto-Balto-Slavic aśmas, from Proto-Indo-European oḱtṓwos, from Proto-Indo-European oḱtṓw, from Proto-Indo-European aḱ- — sharp, pointed; sharp, pointed, edgy; sharp,...

osmiúhelník (Czech): octagon

Definitions

octagon

Ancestry of “osmiúhelník”, step by step

osmiúhelník traces back through two separate lines of ancestry.

via Czech osm

Step	Language	Word	Meaning
1	Czech	osm	eight
2	Old Czech	osm	eight
3	Proto-Slavic	osmь	eight
4	Proto-Balto-Slavic	aśmas	—
5	Proto-Indo-European	oḱtṓwos	eighth
6	Proto-Indo-European	oḱtṓw	eight
7	Proto-Indo-European	aḱ-	sharp, pointed; sharp, pointed, edgy; sharp,...

via Czech úhel

Step	Language	Word	Meaning
1	Czech	úhel	angle
2	Proto-Slavic	ǫglь	coal
3	Proto-Balto-Slavic	anˀglís	coal, charcoal
4	Proto-Indo-European	h₁óngʷl̥	charcoal
5	Proto-Indo-European	h₁engʷ-	to burn; fire

Every word from Proto-Indo-European aḱ- →Every word from Proto-Indo-European oḱtṓw →Every word from Proto-Indo-European oḱtṓwos →