This is the noun midpoint with the addition of two roads or tracks. A track is an ideograph for a journey. The track in the right hand triangle represents the first half of the journey, and the track in the left hand triangle represents the second half of the journey. It follows that this symbol refers to the midpoint on a journey. It is the adjective halfway.
Illustrative Text Reference:
Mohenjo-daro: Seal: M-119 a (Please note that the seal is damaged. Therefore, one edge of this Indus sign is missing in the seal impression.): Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 41: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 2018: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.