air mile

Từ điển WordNet v3.1 - WordNet Dictionary

noun

a unit of length used in navigation;
exactly 1,852 meters;
historically based on the distance spanned by one minute of arc in latitude
• Syn:
nautical mile, mile, mi, naut mi, knot, international nautical mile
• Derivationally related forms:
miler (for: mile)
• Hypernyms:
nautical linear unit