The Indus Dictionary Project
This is a pictograph of a drinking horn. Hence, it is the noun drinking horn.
Mohenjo-daro: Seal: M-402 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 97: Collections in India: Suomalainen Tiedeakatemia.
Although lines drawn across an object normally indicate its size, the position of the lines on this drinking horn appear to depict some kind of grip.
Drinking Horn: Lynn Fawcett, 2018.