Meaning

2 senses
  1. Any of several internationally agreed standard altitudes that are based on atmospheric pressure rather than on true height

  2. A pressure altitude measured in terms of hundreds of feet above sea level (ie. flight level 120 (FL120) is 12,000 ft. ASL)

Forms

plural: flight levels
Singularflight level
Pluralflight levels

regular

See also

neighbours in the dictionary
flight level — meaning, examples, forms, synonyms | Krumeto