The Spotlight node can be used with a Blender Area light or as part of an emission material on a polygon to create a realistic spotlight behavior. The node is typically connected to the Distribution pin on a Texture Emission or Blackbody Emission node (figure 1).
Figure 1: The Spotlight node used to distribute spotlight-like illumination for a Blender Area Light.
Orientation- Determines how the cone will be oriented; the choice will use the coordinates in the Direction or Target edit fields.
Direction or Target - The direction of the light or the target object.
Cone Angle - The angle of the actual cone. Smaller values produce a tighter cone.
Hardness - Sets the hardness of the penumbra (cone) boundaries. Lower values produce a softer look.