ետրոնին

As has been correctly noticed by J̌ahukyan, from Ancient Greek ἑταῖρον (hetaîron), the accusative of ἑταῖρος (hetaîros). The ending -ին (-in) is probably the genitive-dative marker -ի (-i) + the article -ն (-n).

ետրոնին • (etronin)

1. comrade

Attested only in Baṙgirkʻ hayocʻ.

• ընկեր (ənker)

• ետր (etr)

• Eremia Meġrecʻi (1698) “ետրոնին”, in Baṙgirkʻ hayocʻ [Armenian Dictionary] (in Armenian), Livorno: Sargis Evdokiacʻi Sahetʻči Press, page 90
• Ačaṙean, Hračʻeay (1973) “ետրոնին”, in Hayerēn armatakan baṙaran [Armenian Etymological Dictionary] (in Armenian), 2nd edition, a reprint of the original 1926–1935 seven-volume edition, volume II, Yerevan: University Press, page 33b
• J̌ahukyan, Geworg (1963) “Stugabanutʻyunner [Etymologies]”, in Patma-banasirakan handes [Historical-Philological Journal]‎^[1] (in Armenian), number 4, Yerevan: Academy Press, page 91
• J̌ahukyan, Geworg (2010) “ետրոնին”, in Vahan Sargsyan, editor, Hayeren stugabanakan baṙaran [Armenian Etymological Dictionary] (in Armenian), Yerevan: Asoghik, page 219a