A type of traditional headgear worn in families of many Hasidicrabbis, by unmarried children on Shabbat and by rabbis on special occasions. It is a made from brown fur (as opposed to a spodik, worn by Polish Hasidic dynasties, which is fashioned out of black fur).
The word originated from a Turkish word for this kind of hat, kalpak.
English Wiktionary. Available under CC-BY-SA license.