A unit of length used in marine navigation that is equal to a minute of arc of a great circle on a sphere. One international nautical mile is equivalent to 1,852 meters or 1.151 statue miles. Please not that this is different to a UK Nautical mile.
A lightyear is the distance that light travels in one year. Since there are various definitions for the length of a year, there are correspondingly slightly different values for a lightyear. One lightyear corresponds to about 9.461e15 m, 5.879e12 mi, or 63239.7 AU, or 0.3066 pc.