The term 'Main Channel' can refer to two different solutions in a crossword puzzle. The first solution is 'ARTERY, ' which is a type of blood vessel that carries oxygenated blood away from the heart and to the rest of the body. The second solution is 'AORTA, ' which is the largest ARTERY in the human body and is responsible for carrying oxygenated blood from the left ventricle of the heart to the rest of the body.