A yarmulke, also called a kippah, is a skullcap traditionally worn by observant Jews, usually men. It is typically thin and small, but may be made in a variety of fabrics, colors, and designs. Larger yarmulkes, which cover the entire head nearly to the ears, are worn by certain groups. Yarmulke is a Yiddish word derived from the Polish word for "cap."
The Talmud, a collection of ancient Rabbinic writings, refer to a head covering, but it is a matter of debate whether it is meant to be worn all the time or only during prayer, as well as whether wearing a yarmulke is a matter of Jewish law or custom. In any case, the specific type of head covering is not discussed, but the yarmulke may have become the norm because of its small size and convenience. As with many Jewish customs, the yarmulke differs significantly among denominations.
Some Jews only wear a yarmulke when engaged in religious activities, while others wear one nearly all the time. Some groups, such as the Haredi, wear fairly uniform yarmulkes - in this case, made of black velvet - while others allow significant personalization. Yarmulkes can be found in all different colors and even decorated with secular images, such as sports team insignia and cartoon characters. Some Jewish groups object to this type of yarmulke.
A yarmulke may be knitted or crocheted as well. Members of the Israeli Religious Zionists, the Breslov Hasidim, and Kabbalist followers wear fairly large, knitted yarmulkes. The Breslov yarmulke is white and inscribed with the mantra Na Nach Nachma Nachman Me'uman in black Hebrew letters. The phrase makes reference to Rabbi Nachman of Breslov, founder of the movement. The Kabbalist yarmulke is usually made of a dark-colored yarn.
Some Jewish men wear a larger hat over a yarmulke; members of the Haredi, for example, traditionally wear fedoras. Jewish women are subject to the same head-covering tradition as men. Though women in more traditional Jewish groups may cover their heads with a scarf, shawl, or hat, those in non-Orthodox groups sometimes wear a yarmulke.