قُلْ هُوَ اللَّهُ أَحَدٌ
Qul huwa Allahu ahad
De ki: O Allah birdir.
Say: God is one.
Aḥad rather than wāḥid is the choice that carries this surah. Both words mean one, but aḥad refuses division and comparison in a way that the ordinary numeral does not, which is why it resists being made into a plural or a fraction. The surah also opens as an instruction to speak, so what follows is given as an answer, and the early reports place a question behind it.