is a specific kind of: linear measure, linear unit | metric, metric unit.

is a broader term that covers: femtometer, femtometre, fermi | micromicron, picometer, picometre | A, angstrom, angstrom unit | micromillimeter, micromillimetre, millimicron, nanometer, nanometre, nm | micrometer, micron | millimeter, millimetre, mm | centimeter, centimetre, cm | decimeter, decimetre, dm | m, meter, metre | dam, decameter, decametre, dekameter, dekametre, dkm | hectometer, hectometre, hm | kilometer, kilometre, klick, km | mym, myriameter, myriametre ... show more.