Pre-kindergarten (also called Pre-K or PK) refers to the first formal academic classroom-based learning environment that a child customarily attends in the United States. It begins around the age of four or five in order to prepare for the more didactic and academically intensive kindergarten, the traditional "first" class that school children participate in. Pre-Kindergarten is not required. On the other hand, it acts as a way to prepare children (especially those of a disadvantaged population) to better succeed in a kindergarten (often compulsory in many U.S. states).
Pre-kindergartens, though, differentiate themselves by equally focusing on harvesting a child's (1) social development, (2) physical development, (3) emotional development, and (4) cognitive development. They commonly follow a set of organization-created teaching standards in shaping curriculum and instructional activities/goals. The term "preschool" more accurately approximates the name "pre-kindergarten", for both focus on harvesting the same four child development areas in subject directed fashion. The term "preschool" often refers to such schools that are owned and operated as private or parochial schools. Pre-kindergartens refer to such school classrooms that function within a public school under the supervision of a public school administrator and funded completely by state or federally allocated funds, and private donations.