upper school 
noun
1(In the UK) a secondary school for children aged from about fourteen upwards, generally following on from a middle school.Today, she regularly visits other Montessori middle and upper schools across North America and around the world, observing and consulting....
- Bedfordshire County Council operates a three-tier education system, with lower, middle and upper schools.
- If we raise money from selling off shops in Bingley to use on upper schools or special schools, then that seems a sensible use of our capital.
1.1The section of a school which comprises or caters for the older pupils.Around 400 Year 9 to Year 13 pupils from the upper school building spilled into the town centre to oppose war as police were called to try to dispel the crowds....
- Half of the pupils at the upper school will spend the day at Lockeridge with the infants' classes.
- The middle school is on the same campus as the upper school but we used separate buildings.