This is the 6973rd most frequent Russian word.
армянской
"Армянской" means "Armenian" (adjective, feminine or modifying feminine nouns).
Here 'армянской' is an adjective in the genitive case, modifying 'кухни' (cuisine) to describe its origin or style as belonging to Armenia.
Я люблю блюда армянской кухни.
I love dishes of Armenian cuisine.
In this sentence, 'армянской' acts as an adjective in the genitive case, describing 'пряжи' (yarn), indicating its origin.
Она купила армянской пряжи для вязания.
She bought Armenian yarn for knitting.
Here, 'армянской' is an adjective in the prepositional case, describing 'свадьбе' (wedding), denoting the cultural or ethnic association.