Arabic is a Semitic language, as is its distant cousin Hebrew. Both languages are based on roots made up of three consonants. For example, many words can be derived from the root S-L-M (Sh-L-M in Hebrew). Keep your eye on the uppercase letters to follow the root. A basic verb from that root, SaLiMa, means to be safe or whole. A related Arabic noun is salaam, meaning “peace” (like the Hebrew ShaLoM), which is part of a standard greeting among Muslims. When Arabic speakers want to build further meanings on a particular root, they do so by modifying the root with either prefixes, infixes (modifying interior letters), or suffixes. For example, to convey the notion of “causing someone to be safe or at peace,” one modifies the root SaLiMa so that it becomes aSLaMa.

In religious terms, to bring about a state of safety, peace, and wholeness, one has to get one’s relationship to God in perfect order. That means letting God be God, and giving up all pretense at trying to do what only God can do—in short, surrendering to the supreme power. That state of surrender is called iSLaaM, and a person who acts in such a way as to cause that state is called a muSLiM. One of the first major non-Semitic languages early Muslim conquerors encountered was Persian, in which the u was pronounced as an o, and the i as an e. Hence the variation so common today, Moslem. Both mean exactly the same thing; the variations are entirely due to differences in pronunciation.