operational encirclement

Etymology
Chiefly from. In frequent use since the beginning of the, but already before most usage seems to have been in reference to Russia and the Soviet Union.

Noun

 * 1)  a situation of (partial) encirclement where the besieged forces are not yet in imminent danger of destruction or capture, but are unable to organize adequate defence for a longer period of time, especially in such a way that there remains a connection to the rear, which the enemy however can cover with precise artillery fire, severely hampering supply