Chilla (retreat)
Spiritual practice in Sufism
From Wikipedia, the free encyclopedia
Chilla (Persian: چله, Arabic: أربعين, both literally "forty"), also known as Chilla-nashini, is a spiritual practice of penance and solitude in Sufism known mostly in Punjabi,[1] Bengali and Persian traditions. In this ritual a mendicant or ascetic attempts to remain seated in a circle practicing meditation techniques without food for 40 days and nights in imitation of the Arba'een.[2][3]

Etymology
The word chilla is derived from the Persian word chehel "forty".[4]
Chilla-khana
Incidents of Chilla
In music
A practice similar to chilla is also performed by Hindustani classical music practitioners at an advanced level. It is called chilla katna.