O Level Definition
    noun
  
 The earlier of two standardized tests in a secondary school subject.
 American Heritage 
The first, or ordinary, level of standardized examinations in specific subjects taken by British secondary-school students seeking either a General Certificate of Education and university admission or a Certificate only.
 Webster's New World 
A pass on any examination at this level.
 Webster's New World 
Alternative spelling of O-level.
Wiktionary 
A subject-based qualification superseded in England by GCSEs, but still available as an international examination.
Wiktionary 





