Where does “อิสลาม” come from?

อิสลาม (Thai) comes from Arabic إِسْلَام, from Arabic أَسْلَمَ, from Arabic ل, from Proto-Semitic *lV-.

Ancestry of “อิสลาม”, step by step

Step	Language	Word	Meaning
1	Arabic	إِسْلَام	submission; religious submission to God, Islam;...
2	Arabic	أَسْلَمَ	to surrender, to become a Muslim; he submitted
3	Arabic	ل	to, for, belonging to; لَـ •; Used to express...
4	Proto-Semitic	*lV-	—

อิสลาม — Etymology, Origin & Word History | Etymology Explorer