Scouting/Uniform

Uniform
Uniform - MeritBadgeDotOrg - http://meritbadge.org/wiki/index.php/Uniform

Activity Uniform
"The Activity Uniform is a Scouting-related T-Shirt and scout pants." 

"Troops and Packs are free to create their own Activity shirt. The most well-known place to design and purchase these shirts is ClassB.com which is a full-service web site offering custom t-shirts and patches. They are an official licensee of the Boy Scouts of America, have a great reputation of service and quality products since 1982, and have Eagle Scouts running the company." 

"While the official uniform should be worn to all den and pack meetings and formal events, the den or pack may designate a special-purpose uniform, such as the Cub Scout Activity Shirt (shown here) to be worn in place of the official uniform shirt for certain activities, such as sporting events or day camp." 

Class A & Class B Uniform
The official term for the uniforms are "Field Uniform" (Class A) and "Activity Uniform" (Class B).

"These two uniforms (Field and Activity) are often referred to as Class A and Class B uniforms though that terminology is not used in any official BSA publications and is not correct. It would be better to call them Field and Activity uniforms following the BSA terminology."