Use the word gentile to mean non-Jewish, like the gentile friend you invite to your family's Passover Seder because she's curious about Jewish religious traditions.
When Gentile is a noun, it's usually capitalized, and it's most frequently used to contrast a Christian with a Jew. There are other religions that use the word gentile to describe a non-believer, including Mormonism and Hinduism. More generally, gentile refers to a person who doesn't acknowledge a particular god or belief. The root is the Latin gentilis, whose meaning of "fellow countryman or family member" changed over time to mean "foreign, heathen, pagan."
