ёстой

Inherited from Classical Mongolian ᠶ᠋ᠣᠰᠤᠲᠠᠢ (yosutai, ornative), from Middle Mongol [Term?] (feminine singular ornative). By surface analysis, ёс (jos) +‎ -той (-toj, comitative suffix). Cognate with Khamnigan Mongol ёсотой (josotoj), Buryat ёһотой (johotoj), Kalmyk йоста (yosta), etc. Compare also Tuvan ёзулуг (yozulug).

• (Khalkha) IPA^(key): [jɔs.tʰœː]
• Hyphenation: ёс‧той

ёстой • (jostoj) (comitative)

1. proper
2. just
3. (modal, after a verb in infinitive -х⁵ (-x⁵)) Used to form the debitive mood.

   Synonym: зүйтэй (züjtej)

• “ёстой”, in Монгол хэлний их тайлбар толь [Dictionary of the Mongolian Language] (in Mongolian), Institute of Linguistics of the Mongolian Academy of Sciences, 2016–present

ёстой • (jostoj)

1. comitative of ёс (jos)