Wagon trains — groups of wagons — rode in four lines across the land when they passed through dangerous country. If attacked, the wagons could quickly form a circle for defense.

马车队(即一群马车)，当他们经过危险区时，他们排成四排向前行进，如果遭受到攻击时，这些马车就会很快地形成一个保护圈进行抵抗。

youdao

An enclosure formed by a circle of wagons for defense against attack during an encampment.

车阵用运货车围成的围栏，用作营地的防御地区。

youdao

If attacked, the wagons could quickly form a circle for defense.

VOA: special.2009.03.30

To a significant degree, U.S. defense strategy has come full circle.

CENTERFORSECURITYPOLICY: Center for Security Policy | The Measure of a Superpower: A Two Major Regional Contingency Military for the 21st Century | Page: 2

Mike Weaver passed the puck from the right point to his defense partner on the left side and his shot from the top of the circle found the upper corner of the net.

WSJ: Devils rally 6-2 vs Panthers, keep playoff hopes

Brennan faked a shot at the right point and slid a pass across the zone to defense partner Campbell, who fired a slap shot from the upper inside edge of the right circle that appeared to clip the stick of Rangers defenseman Ryan McDonagh before it sailed past Lundqvist at 8:22.

WSJ: Markstrom, Panthers stop Rangers 3-1