the side of a person or animal, between the ribs and the hip
left or right side of an army or a body of troops
place sb/sth on each side or at the side of
"they attacked the enemy's right flank"
The Redwing..can be distinguished by its long pale eye-stripe and reddish flanks.
出自： T. A. Coward
From the hip to the knee her flank was against his.
出自： G. Orwell
An advanced angle..with shot-holes for flanking the door-way.
出自： Sir W. Scott
The second division flanks on the main of force.