linear unit - a unit of measurement of length

air mile, international nautical mile, mile, naut mi, nautical mile, mi, knot - a unit of length used in navigation; equivalent to the distance spanned by one minute of arc in latitude; 1,852 meters

Admiralty mile, geographical mile, naut mi, nautical mile, mi, mile - a British unit of length equivalent to 1,853.18 meters (6,082 feet)

sea mile, mile - a former British unit of length once used in navigation; equivalent to 1828.8 meters (6000 feet)