Platoon is a english signification for a military unit, which is composed of 16 to 50 soldiers. A platoon is the smallest tactical unit. Serveral platoons put together a company.
The soldiers were led by a non-commissioned officer, the platoon sergeant, he assists the platoon leader (usually a lieutenant). The US-Marines and most of the Commonwealth NAtions call their leader of the platoon Platoon Commander. The word "platoon" derived from the french term peloton, which means a small unit of soldiers.