This symbol is related to the Chinese character tài 太. The position of the point of light in the leg area tells us that this is a person of standing. Hence, Mahadevan's sign number 3 is
the adjective superior. In both Chinese and Indus script, the symbol can also take the meaning of very big or large.
Sample Text Reference:
Mohenjo-daro: Seal: M-123 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 42: Collections in India: Suomalainen Tiedeakatemia.
Indus Script Sign Number 3: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.