A Jewish day school is a modern Jewish educational institution that is designed to provide Jewish children with both a Jewish and a secular education in one school on a full time basis, hence its name of "day school" meaning a school that the students attend for an entire day and not on a part time basis. The substance of the "Jewish" component varies from school to school, community to community, and usually depends on the Jewish denominations of the schools' founders. While some schools may stress Judaism and Torah study others may focus more on Jewish history, Hebrew language, Yiddish language, secular Jewish culture, and Zionism.
History
Jewish day schools were established in great numbers after World War II in the United States and in other Western countries such as Canada, England, South Africa, Australia, and in South America. In the United States the dislike for, and decline of, the old-fashioned Talmud Torahs and a disenchantment with public schools led to a push for the formation of full-time all-day dual-curriculum Jewish schools, or as they are sometimes described "schools for Jews."
Types
Not all Jewish day schools are the same. While they may all teach Jewish studies or various parts of Torah and Tanakh, yet these studies may be taught from various points of view depending on each school's educational policies, the board of directors in charge, and the nature and make-up of both the student body and the professional teaching staff.
Some day schools may be entirely religious, and indeed most yeshivas (Orthodox schools that emphasize Talmudic studies) are a variety of day schools. However the traditional yeshivas are different institutions when compared to Modern Orthodox Jewish day schools. While traditional Haredi and Hasidic yeshivas are only for boys, with girls attending Beis Yaakov schools, that do not encourage their students to plan for college education and professional careers, on the other hand Modern Orthodox day schools are usually coeducational and will stress the secular component of the curriculum precisely because the parents wish to have their children educated on a high enough level to be admitted to the finest colleges and universities in order to train for a profession.
The Solomon Schechter Day Schools in the United States and Canada teach Judaism from the perspective of Conservative Judaism, and there are schools that similarly teach Judaism from a Reform or even non-denominational perspective. These latter are usually called pluralist day schools, and many belong to RAVSAK, a network of pluralist day schools.
Jewish day schools may be entirely secular. One of the largest day schools in the world is the King David School system in Johannesburg, South Africa that educated thousands of Jewish students stressing the teaching of Hebrew language and Zionism, with a modicum of Judaism since the majority of students and the teachers are not fully religiously observant.
Numbers
There were 802 Jewish day schools in USA in 2008-2009, with an enrollment of 228,174 children from age 4 to grade 12.