junior school

Short definition from Wiktionary

Noun

1. 1
   A school providing primary education to children: A school providing education to children in Key Stage 2, i.e. for four academic years from September after a child's 7th birthday.
2. 2
   A school providing primary education to children: Usually a part of a private school that educates children between the ages of 2 and 5.
3. 3
   A school providing primary education to children: A school teaching children from kindergarten to Grade 5; an elementary school.