Traditionally understood to include the provision of early education to 3, 4, and 5 year-old children who are not old enough for kindergarten. Programs usually are administered by state education authorities and are open either half-day or during school hours (9 a.m. to 3 p.m.). This term is also used generically to refer to services for preschool-age children (4 and 5 year-olds). Preschool tends to include pre-kindergartens and nursery schools.
A beginning group or class enrolling children younger than 5 years of age and organized to provide educational experience under professionally qualified teachers in cooperation with parents during the year or years immediately preceding kindergarten (or prior to entry into elementary school when there is no kindergarten).