Many in the West know that Muslims worship "Allah." Especially among Evangelical Protestants, though, some are under the misimpression that the term "Allah" refers to a pagan moon deity from pre-Islamic Arabian mythology. Certainly, in their view, it has nothing to do with the God of Christianity. Muslims are, they claim, worshiping a false god.

But, in fact, "Allah" is simply the Arabic equivalent of the English word "God." It's a contraction of two words, the Arabic definite article "al" (essentially equal to English "the") and the Arabic noun "ilah," meaning "god" with a lower case "g." Arabic script has no capital letters, so attaching the definite article to "ilah" serves the purpose. While "ilah" can refer to a pagan "god," "Allah" cannot. Instead, it designates...