This symbol shares the same root as the Chinese character huí 回. It is the verb to return.
Sample Text Reference:
Mohenjo-daro: Ivory Rod: M-2090 B: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 121: New material, untraced objects, and
collections outside India and Pakistan: Suomalainen Tiedeakatemia.
The character has its origin in the word echo. The outer ring is the boundary wall, and the inner ring is the reflected sound.