This is the noun house to which a stylised right hand has been added. The right hand signifies friendship. Hence, Mahadevan's sign number 282 is an ideograph for a friend's house, home or dwelling place.
Illustrative Text Reference:
Kalibangan: Seal: K-15 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 301: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 282: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.