This is the 10020th most frequent Russian word.
артиллерийскую
The Russian word "артиллерийскую" means "artillery" (adjective, feminine accusative form).
The word "артиллерийскую" is in its feminine accusative singular form, modifying "установку," to describe that it is related to artillery.
Они использовали артиллерийскую установку для обстрела крепости.
They used an artillery installation to shell the fortress.
"Артиллерийскую" here agrees in gender (feminine) and case (accusative singular) with "батарею," specifying its relation to artillery.
На берегу реки была размещена артиллерийскую батарею.
An artillery battery was placed on the riverbank.
The adjective "артиллерийскую" is used before "позицию" in the accusative singular form to indicate its connection to artillery.