This is a pictograph of a star. Hence, it is the noun star.
Illustrative Text Reference:
Harappa: Seal: H-1534 A: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 211: New material, untraced objects, and collections
outside India and Pakistan: Suomalainen Tiedeakatemia.
There is only one extant example of this Indus sign. It appears as the sole character on a seal. It may therefore be an instance of the word star functioning as a proper name.