Where does “एक” come from?

एक (Maithili) comes from Sauraseni Apabhramsa एक्क, from Sauraseni Prakrit 𑀏𑀓𑁆𑀓, from Ashokan Prakrit 𑀏𑀓, from Sanskrit एक, from Proto-Indo-Aryan Háykas, from Proto-Indo-Iranian Háykas, from Proto-Indo-European óynos — one; single.

एक (Maithili): one

Definitions

Ancestry of “एक”, step by step

Step	Language	Word	Meaning
1	Sauraseni Apabhramsa	एक्क	one
2	Sauraseni Prakrit	𑀏𑀓𑁆𑀓	one
3	Ashokan Prakrit	𑀏𑀓	one
4	Sanskrit	एक	one; alone, solitary, single, happening only...
5	Proto-Indo-Aryan	Háykas	one
6	Proto-Indo-Iranian	Háykas	one
7	Proto-Indo-European	óynos	one; single

Every word from Proto-Indo-European óynos →Every word from Proto-Indo-Iranian Háykas →Every word from Proto-Indo-Aryan Háykas →