Sacred Assignment
Niyamanam (Sanskrit: niyamana = regulation, appointment, assignment; Tamil: niyamanam) in Śrī Vaiṣṇava usage refers to a task, appointment, or assignment given by the Ācārya or by Bhagavān — a specific service one is asked to perform within the tradition's structure.
Ācārya's Mandate
When an Ācārya assigns a disciple a specific form of service — composing a commentary, managing a temple, teaching a class — this is a niyamanam. Executing the Ācārya's niyamanam with full devotion is considered the highest form of kaiṅkarya. Piḷḷai Lokācārya's composition of the 18 Rahasya Granthams, for example, is understood as his fulfillment of the niyamanam received through the lineage from Nāthamunigaḷ.
Divine Appointment
More broadly, each soul's existence in the present body and circumstances is itself a kind of niyamanam from Bhagavān — a specific situation within which to render service and progress toward liberation. The tradition encourages understanding one's life-circumstances not as random fate but as the Lord's sovereign arrangement (niyantā = the One who arranges).