The term 'Certain Military Force' can be summarized by two crossword solutions: ARMY (4 letters) and RedArmy (7 letters). The ARMY is a branch of the United States Armed Forces that is responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of the seven uniformed services of the United States. The Red ARMY was the name given to the Soviet Union's armed forces from 1918 to 1946. It was the largest and most powerful military force in the world during World War II, and was instrumental in defeating Nazi Germany.