This is the 18344th most frequent Russian word.
щитов
"Щитов" is the genitive plural form of "щит," meaning "shields."
Here, 'щитов' is used in its plural form as the genitive case indicating 'of shields' in the sense of objects used for protection.
Мы собирали щитов для укрепления обороны.
We were assembling shields to strengthen the defense.
In this sentence, 'щитов' again appears in the plural genitive form, referring to the material 'iron shields' specifically illustrating their defensive utility.
Железных щитов хватило, чтобы отразить атаку.
The iron shields were enough to repel the attack.
Here, 'щитов' is used to denote 'of these shields,' indicating possession or association with their design.