One of the few Finnish words used in English.
1. One cubic metre, specifically of firewood.
2. A "siege" tactic used in military operations. The mass of the enemy troops are enclosed in a circle of light infantry, which are on skis in winter. The enemy's supply route is cut, so that they're on their own and they start to starve. You "cut" a motti, to be collected later.
This is useful if you're low on ammo and troops, like the Finnish Defence Forces were in the Winter War. Only a few troops and ammo are needed to sustain a successful motti. You need to fire at the enemy only when they try to light a fire or escape the siege. The enemy has to remain cautious all the time. In the winter, without the fire, the enemy freezes to death. The enemies starve and they are demoralized. In the night, you can easily sneak in without being noticed and kill enemies with a knife.
Finns deliberately planned an operation using the tactic only once in the Winter War. However, the Soviet doctrine of not receding any land meant that the motti tactic was very effective, and was used by the Finns many times. A motti bound a lot of enemy forces, but was quite hard to destroy, so many of them remained until the end of the war. The most famous of all was in Raatteentie, where a convoy was stopped and destroyed.
My friend's grandfather told how he and his company attacked a Soviet motti without firing a single shot. They encircled a camp, sneaked in and slit their throats silently. One Soviet was left alive and commanded to go and tell - and effectively demoralize - others.
A recent war, the Gulf War II, was all about motti's. The American vanguard (mainly U.S. Marines) left a lot of sieges behind, which were tackled with later by the occupying troops. The Iraqis didn't retreat from bigger cities. Note that the Iraqi army tactics are mostly inherited from the Soviet Union. The Soviets and the Iraqi didn't know the concept of tactical retreat, which left them highly vulnerable to motti tactics. The American army was not only overpowering, but also had better tactics.