It is perhaps the most instantly identifiable mark of a Jew.

In the Western world, it is customary to remove one's head covering when meeting an important person. In Judaism, putting on a head covering is a sign of respect.

The uniqueness of a Jewish head covering is hinted at in the blessing we say every morning, thanking God for "crowning Israel with splendor" (Talmud - Brachot 60b)

The kippah is a means to draw out one's inner sense of respect for God. 
 
The Talmud says that the purpose of wearing a kippah is to remind us of God, who is the Higher Authority "above us" (Kiddushin 31a). External actions create internal awareness; wearing a symbolic, tangible "something above us" reinforces that idea that God is always watching. The kippah is a means to draw out one's inner sense of respect for God.

It's easy to remember God while at the synagogue or around the Shabbat table. But Jewish consciousness is meant to pervade all aspects of our lives -- how we treat others, how we conduct business, and how we look at the world.

Appropriately, the Yiddish word for head covering, "yarmulke," comes from the Aramaic, yira malka, which means "awe of the King."

In Hebrew, the head covering is called "kippah" -- literally "dome."