A synagogue is a Jewish house of prayer and study. The Hebrew term for synagogue is Beit Knesset (House of Assembly) or Beit Tefila (House of Prayer). There are usually separate rooms for prayer (the main sanctuary) and smaller rooms for study. Rooms set aside for study are referred to as Beit Midrash (Hebrew, House of study.)
Synagogues are not only used for prayer, but also for communal activities, adult education and Hebrew schools for school-age children.
Orthodox and most Conservative Jews refer to their houses of worship as synagogues; a few use the Hebrew term Beit Knesset, or the Yiddish term shul. Most Reform and some Conservative Jews use the term "Temple" to describe their house of worship, but most traditional Jews find this term inaccurate, as Judaism has historically only had one Temple, the Temple in Jerusalem.
Most Conservative and Orthodox synagogues have prayer services every day; usually one morning service, and two evening services. There are special services on Shabbat (the Sabbath) and on the Jewish holidays. Many Reform Temples only have prayer services once or twice a week.
Many Jews have a regular place of worship that is not a synagogue by the usual definition of the term. Many ultra-Orthodox Jews worship in shteibels (literally, "little booths"), rooms in private houses or places of business set aside for the express purpose of prayer. Shteibels do not offer the communal services of a synagogue, and are for prayer services alone. Many non-Orthodox Jews have formed chavurot (prayer fellowships) which meet at a regular place and time, usually in someone's house or apartment.
See also: Siddur -- Jewish services -- Role of the cantor in Judaism -- Jew -- Church -- Mosque