Where does “երկոքին” come from?

երկոքին (Old Armenian) comes from Old Armenian -եքին, from Proto-Indo-European -ēs, from Proto-Indo-European -ess, from Proto-Indo-European -os — Creates action nouns or result nouns from verbs;...

երկոքին (Old Armenian): both

Definitions

both

Ancestry of “երկոքին”, step by step

Step	Language	Word	Meaning
1	Old Armenian	-եքին	forming collective numerals
2	Proto-Indo-European	-ēs	Primarily forms adjectival bahuvrīhi compounds
3	Proto-Indo-European	-ess	—
4	Proto-Indo-European	-os	Creates action nouns or result nouns from verbs;...

Every word from Proto-Indo-European -os →Every word from Old Armenian -եքին →Every word from Proto-Indo-European -ēs →