Flanck

The Musketeers being on both flancks, firſt firing let the Ranck ſtand, and fire every Ranck, paſſing through before his leader[…]

Source: wiktionary

But he was never heard to ſay, that it was I, that gave this Command, who took the Enemies in the flanck,[…]

Source: wiktionary

[…]commanded that part of his cavalery which was behind his foot, to charge the King's and the general's regiments in the flanck, just at the time when they were so warmly ingaged at push of pike with his men.

Source: wiktionary