A formation or rank—an orderly line or column of troops, people, or vehicles; the arrangement used in parades or marches.
式典で隊列が整って入場した。
At the ceremony, the columns formed up and entered in order.
隊列の先頭を務めるのは経験のある隊員だ。
The person at the head of the formation is an experienced member.
行進中は隊列を乱さないように気をつけてください。
Please be careful not to break formation during the march.