Interpreting the "script" or pictographs of Indus Valley seals remains a major scholarly challenge.
Scholars have been unable to decipher this or any seal's script. However, a number of directions are emerging after decades of analysis.
Two leading scholars, Asko Parpola (in Finland) and Iravatham Mahadevan (in India), agree that the pictographs probably represent a proto-Dravidian language like Tamil (common in Southern India today). Mahadevan has attempted a reading of the terminal signs on some seals through the aid of computer analysis.
Mahadevan looks closely at the five most common terminal signs on Indus seals.
Two of the signs are clearly combinations of two other terminal signs with the (above center) sign apparently indicating someone carrying something, or a bearer.
Mahadevan argues that the signs represent the titles, class or profession of the seal's users, and that these names and titles may have been passed on to later Indian languages as loan words. In particular, he suggests that the first sign (above), the most frequent sign in Indus script, denotes a jar, which is related in later Indian traditions to priestly ritual.
Thus Mahadevan would read the final sign of the unicorn seal here as denoting an officer or priest with official duties, which supports Mackay's early speculation about its owner's status.
Nevertheless, these interpretations are far from being proven.