Definitions of troop:

• noun:   a group of soldiers
• noun:   a cavalry unit corresponding to an infantry company
• noun:   an orderly crowd

  Example: "A troop of children"

• noun:   a unit of girl or boy scouts
• verb:   move or march as if in a crowd

  Example: "They children trooped into the room"

• verb:   march in a procession
• name:  A surname (very rare: popularity rank in the U.S.: #19912)