There are as many different interpretations of shade garden types as there are books written about shade.
For the sake of consistency, we are using plant shade definitions from the American Horticultural Society in its book Gardening in Shade (DK Publishing, 1999).
Light shade is a permanent shade cast by the shadow of a building, wall, hedge, or tree on a site otherwise exposed to the sky and open to light. It offers the most opportunity for blooming plants that otherwise like the sun.
After light shade, partial shade provides the next best opportunity for flowers in shade. Under these conditions, an area receives up to 6 hours of direct sun, with four or more of those hours being in the morning, and the rest of the day being in shadow. It is the most beneficial for a variety of plants. (Note that if 4 or more of the 6 hours of sun are in the afternoon, it is considered to be full sun.)
Dappled or Filtered
Dappled or filtered shade is created by sunlight filtering through the canopy of open tree branches or through latticework structures, with the pattern of light shifting all day. This is probably the most common shade in suburban backyards and is also the most common woodland shade-garden environment.
Deep or Full
Deep or full shade is the dense kind of shade found under evergreens or closely spaced shrubs and trees that do not allow any direct light to penetrate. This is the most cooling kind of shade but is also the most difficult; it takes effort to find plants that will bloom here. But it also can be the most interesting, because the plants suited to it tend to have the best leaf structure.