This is the 10012th most frequent Russian word.
армий
The word "армий" is the genitive plural form of "армия," meaning "armies" in English.
The word "армий" is used in the genitive plural form to refer to multiple armies as objects of discussion.
Русская литература рассказала нам о храбрости и победах древних армий.
Russian literature has told us about the bravery and victories of ancient armies.
Here, "армий" is used in the genitive plural form, denoting possession or association in the context of the models related to armies.
На выставке были представлены модели армий различных стран.
At the exhibition, models of armies of different countries were displayed.
In this sentence, "армий" adopts the genitive plural form, emphasizing the analysis of the plans and operations of multiple armies.