from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A detachment of troops that protects the rear of a military force.
from The American Heritage® Dictionary of the English Language, 4th Edition
Lieutenants Armstrong and Reed formed the rear guard.
After all, the providential appearance of the fog saved a part of our army from being captured, and certainly myself among others who formed the rear guard.
The third Infantry brigade with its Mountain battery and one or two troops of Cavalry formed the rear guard.
Horsan the Dane, with his company, formed the rear guard.
And now it was the division Loison which formed the rear guard.
"General Heron reports that the two battalions under your command fought with extraordinary steadiness, and repulsed all the attempts of his cavalry to break them; and finally succeeded in drawing off to the mountains, with the exception of the two companies that formed the rear guard.