The Sanskrit word Sadhana is defined as spiritual practice or exertion toward yoga with the Cosmic Spirit.
Within the International Nath Order, sadhana is the daily work by which that exertion is made real. A petitioner or Nath keeps a zonule—a dedicated place with an altar and the elements—and uses it for mantra, japa, puja, and meditation. The Order asks for a steady period of practice (commonly sixty to ninety minutes) and a sadhana journal so that thought, experiment, and result can be seen over time. Initiation transmits a link; sadhana is what moves the work forward.