In the Scout Movement, a Scout troop is an organizational unit consisting of a number of patrols of Scouts, Boy Scouts, Girl Scouts or Girl Guides. Girl Guides often use the terms "unit" instead of patrol and "company" instead of troop. The initial organization unit in the Scout Movement was a patrol of about 6 to 8 Scouts. Where there were a number of patrols, they could form a Scout troop. Scout troops are composed of boys and/or girls usually aged 10 to 18 years. Some Scout organizations have senior Scout patrols within Scout troops or senior Scout troops for the older youths. The size of a Scout troop can vary from as few as six Scouts to several dozen. Scout troops may meet regularly at a meeting place. In addition, some Scout troops are active in the organization of additional activities.