A troop is a military sub-subunit, originally a small formation of cavalry, subordinate to a squadron. In many armies a troop is the equivalent element to the infantry section or platoon. Exceptions a
K Troop, 9th U.S. Cavalry
A platoon is a military unit typically composed of two to four squads, sections, or patrols. Platoon organization varies depending on the country and the branch, but a platoon can be composed of 20–50
Platoon of marines from the United States Marine Corps, 1945