Egyptian Hieroglyph S031

S31 is a phonogram: its scholarly written value is smꜣ. Egyptologists use that transliteration as a writing convention, not as a guide to ancient pronunciation. S31 combines a folded-cloth sign with a sickle and contributes sound inside a word.

A sign-list example uses S31 in smꜣ, translated “fighting bull.” That meaning belongs to the full written word, not to S31 alone. The same value appears in words about joining, including the royal title smꜣ-tꜣ.wj, translated “Uniter of the Two Lands.”

Is S31 the Egyptian union sign?

No. F36 𓄥 is a different sign that can also write smꜣ. F36 depicts a windpipe and lungs and can stand for the word “lung”; S31 combines folded cloth and a sickle and writes smꜣ phonetically. They share a reading, but their forms and functions differ.

Surviving examples of smꜣ run from Unas, an Egyptian king, through Ramesses II. In those texts, F36 can stand for “lung” as a whole word, while S31 appears phonetically in royal, territorial and funerary formulas.