Square Gy

It lets a Latin unit abbreviation fill one East Asian character cell.

The gray (Gy) became a unit in the International System of Units (SI) in 1975; it measures energy deposited by radiation per kilogram of material. In Chinese, Japanese, and Korean typography, a character often takes a full square cell; this form lets the two Latin letters occupy one such cell.

This set of square Latin unit abbreviations largely reflects older Korean character standards. Unicode maps ㏉ compatibly to the two letters Gy; text-normalization forms such as NFKC and NFKD can turn it into those plain letters.