3 Realms of Existence:

  1. Realm of sense world
  2. Realm of Form
  3. Realm of the Form-less

avacara
’sphere’, realm. The 3 spheres of existence are:
the sensuous sphere (kāmāvacara),
the fine-material sphere (rūpāvacara),
the immaterial sphere (arūpāvacara).