ARF Almost Ready to Fly

A prefabricated model - Almost Ready to Fly.
Wiki:

An almost ready to fly (ARF or ARTF) kit is a radio-controlled airplane kit that comes partially built, usually just requiring final assembly to complete. They normally include partially assembled wings, along with a fuselage and stabilizers already pre-covered in plastic film sheeting material such as Ultracote or Monokote. The remaining assembly steps usually include the installation of control linkages and surfaces, and the purchase and installation of an engine or electric propulsion system and radio gear.

Though most require full assembly, many injection molded foam kits such as the Grand Wing Servo-Tech Formosa are considered to be almost ready to fly due to the low parts count.

Depending on the complexity of the model, this can take only an hour or as many as twenty hours to complete.
Source: http://en.wikipedia.org/wiki/Almost_ready_to_fly

Angle of Attack

The angle that the wing penetrates the air. As the angle of attack increases so does lift and drag, up to a point.

AMA - The Academy Of Model Aeronautics

The Academy Of Model Aeronautics. The official national body for model aviation in the United States. AMA sanctions more than a thousand model competitions throughout the country each year, and certifies official model flying records on a national and international level.

Ailerons

 
Hinged control surfaces located on the trailing edge of the wing, one on each side, which provide control of the airplane about the roll axis. The control direction is often confusing to first time modelers. For a right roll or turn, the right hand aileron is moved upward and the left hand aileron downward, and vice versa for a left roll or turn.