To circumambulate, is to walk around something. A circumambulatory path is a pathway that is designed to facilitate circumambulation. Passageways on the second story of Humayun's Tomb facilitate circumambulation of the cenotaphs in the main chamber and ancillary chambers.1 In many religions, circumambulation is a form of worship. Mughal tombs were circumambulated as a natural application of Sufi worship practices.2
In the context of Humayun's Garden Tomb, the graves of holy men in the graveyard at Nizam al-Din's chilla-khana are circumambulated by Sufi devotees.
In the larger context of Islam, one of the five pillars of the faith is to complete a pilgrimage to Mecca called the Hajj. An important element of the Hajj is tawaf, circumambulating the Kaaba seven times counterclockwise.3
1. Glenn Lowry, "Humayun's Tomb: Form, Function, and Meaning in Early Mughal Architecture," Muqarnas 4, (1987): 135.
2. Catherine B. Asher, Architecture of Mughal India (Cambridge: Cambridge University Press, 1992), 56.
3."Tawaf," Hajj and Umrah Planner, accessed June 21, 2020, http://hajjumrahplanner.com/tawaf.
Parodi, Laura E. "The Posthumous Portrait of 'Hadrat Jannat Ashiyani:' Dynastic, Saintly, and Literary Imagery in the Tomb of Humayun." Islamic Art 6, (2009): 129-58.
Petersen, Andrew. Dictionary of Islamic architecture. London: Routledge, 1996, 142-43.
Hajj and Umrah Planner. "Tawaf."