Core classes are classes in math, English, natural science, and social science that make up the bulk of most academic curricula, especially in high school and university-level programs. In addition to these classes, students generally are required to take classes in subjects such as the arts and foreign languages. Depending on the academic institution, there may also be physical education classes required as well.
Although it is often requires for students to take classes in the core subjects, they often have some choice in which classes they take within those subjects. For example, under the umbrella of English are classes in composition, speech, and sometimes even creative writing. Furthermore, the literature classes offered within an English department usually vary quite a bit from semester to semester. Therefore, a student might be able to choose from classes in Victorian literature, the Romantic poets, the 20th-century novel, and West Indian literature one semester while being able to choose between courses in Shakespeare's sonnets, feminist literature, post-colonial literature, and Asian literature the next. Sometimes these choices are only available after completing a prerequisite core class such as freshman composition.
There may be a bit less variety in core classes that fall under the umbrella of math, natural science, and social science, but there are usually still some options from which students can choose. Much like with English core classes, the elective classes in these fields are often available only after completing prerequisite courses, which are often completed in the first year or the first two years of the academic program. Math core classes usually include geometry, algebra, statistics, trigonometry, and calculus. Core classes in the natural sciences often include physics, biology, chemistry, and earth science. History, sociology, anthropology, psychology, economics, geography, and political science are often clustered under the umbrella of the natural sciences.
Depending on one's academic focus or major, more classes may be taken in one core field than the other. For example, a student hoping to complete a major in psychology will likely take far more classes in the social sciences than a student hoping to complete a major in physics. Furthermore, some students will load up on core classes in one particular field in preparation for a second degree that they hope to complete after finishing the requirements for the present one. Students hoping to go on to become doctors, for example, will take many core classes in the natural sciences such as biology and anatomy.