Where does “εξα-” come from?

εξα- (Greek) comes from English hexa-, from Latin hexa-, from Ancient Greek ἑξα-, from Ancient Greek ἕξ, from Proto-Hellenic hwéks, from Proto-Indo-European swéḱs — six.

εξα- (Greek): exa-

Definitions

exa-

Ancestry of “εξα-”, step by step

Step	Language	Word	Meaning
1	English	hexa-	API; six
2	Latin	hexa-	hexa
3	Ancient Greek	ἑξα-	Forming compound words with the sense of "six"
4	Ancient Greek	ἕξ	six
5	Proto-Hellenic	hwéks	cardinal...
6	Proto-Indo-European	swéḱs	six

Every word from Proto-Indo-European swéḱs →Every word from English hexa- →Every word from Ancient Greek ἑξα- →