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 Baṙgirkʿ hayocʿ.

• ընկեր (ənker)

• ետր (etr)

• Eremia Mełrecʿi (1698), “ետրոնին”, in Baṙgirkʿ hayocʿ [Armenian Dictionary] (in Armenian), Livorno: Sargis Evdokiacʿi Sahetʿči Press, page 90
• Ačaṙean, Hračʿeay (1973), “ետրոնին”, in Hayerēn armatakan baṙaran [Armenian Etymological Dictionary] (in Armenian), volume II, 2nd edition, a reprint of the original 1926–1935 seven-volume edition, Yerevan: University Press, page 33b
• J̌ahukyan, Geworg (1963), “Stugabanutʿyunner [Etymologies]”, in Patma-banasirakan handes [Historical-Philological Journal]‎ (in Armenian), issue 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