This ideograph is the phrasal verb to stand out or to stick out. It is the equivalent of the Chinese character tū 凸.
Illustrative Text References:
Harappa: Seal: H-74 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 185: Collections in India: Suomalainen Tiedeakatemia.
Mohenjo-daro: Seal: M-1665 a: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 6: New material, untraced objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
Comment:
There are only two extant examples of this sign in the Indus texts. Both examples are associated with the noun foreigner.
Image Credit:
Indus Script Sign Number 257: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.