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O level vs. A level

[oh lev-uhl] / ˈoʊ ˌlɛv əl /

noun

British.
  1. a public examination for secondary-school students, usually 15 to 16 years old, testing basic knowledge in various subjects, required before advancing to more specialized courses of study.

  2. a pass in this examination.

[ey lev-uhl] / ˈeɪ ˌlɛv əl /

noun

British.
  1. a public examination requiring advanced knowledge in a subject and taken at the end of secondary school, usually two years after O level.

  2. a pass in this examination.