Wikipedia
A shtiebel (, pl. shtiebelekh or shtiebels, meaning "little house" or "little room") is a place used for communal Jewish prayer. In contrast to a formal synagogue, a shtiebel is far smaller and approached more casually. It is typically as small as a room in a private home or a place of business which is set aside for the express purpose of prayer, or it may be as large as a small-sized synagogue. It may or may not offer the communal services of a synagogue.
Traditional shtiebels are not only a place for prayer, but also a place for community gathering. Due to the prominence of a Hasidic Rebbe, the shtiebel served as a medium for being near to him. A shtiebel would be host to the Shalosh Seudos, the ritual third meal of the Sabbath.
Shtiebels were common in Jewish communities in Eastern Europe before the Holocaust. They were popularly preferred to large synagogues by Hasidim, and continue to exist in contemporary Israel and the United States.
In Israel, minyans are held in storefront shtiebelekh in major business areas around the clock; whenever ten men show up, a new minyan begins. The Zichron Moshe shtiebel in the Zichron Moshe neighborhood of Jerusalem (near Geula) is located in a proper synagogue, with many rooms for round-the-clock minyans. This shtiebel is well known as the locale of Friday-night mussar talks which Rabbi Sholom Schwadron, the " Maggid of Jerusalem," delivered for more than 40 years.