Definition of summer session in English:

summer session

noun

Scottish
  • 1A session of a legislative, judicial, or other body which takes place during the summer; formerly also in plural (with singular or plural concord).

  • 2A period of university or school instruction taking place during the summer, especially one that offers courses which are optional, additional, or open to people who are not regularly enrolled students of the institution.

Origin

Late 16th century.