The Indus Dictionary Project
This is a pictograph of a prop or support. Hence, it is the noun prop.
Dholavira: Seal: SI. Number: 32: Acc. Number: 9093 (NB. The photograph is of the seal. Therefore, the inscription would be the mirrored image of that seen in the photograph.): R.S. Bisht, 2015: 8.2.3 Details of Individual Seals: Excavations at Dholavira (1989-90 to 2004-2005), p. 266: https://www.scribd.com/document/262316120/Excavations-at-Dholavifra-1989-2005-RS-Bisht-2015: Accessed: 4 December, 2018.
It is important to distinguish Mahadevan's sign number 161 from the noun wood or timber, which is listed under plant.
Indus Script Sign Number 161: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.