A, G, M, a, angstrom unit, astronomical unit, block, centimeter, chain, chiliad, chiliagon, chiliahedron, chiliarch, chiliarchia, cubit, decameter, decimeter, dekameter, ell, em, en, fathom, finger, foot, footstep, fur, furlong, grand, hand, inch, kilo, kilocycle, kilogram, kilohertz, kiloliter, lakh, league, light-year, line, link, meter, micron, mil, mile, millennium, millepede, milligram, milliliter, myriad, myriameter, nail, one hundred thousand, pace, palm, parsec, perch, pica, point, pole, rod, step, stride, ten thousand, thou, thousand, wavelength, yard

top

ROGET THESAURUS

kilometer

Length

N length, longitude, span, mileage, distance, line, bar, rule, stripe, streak, spoke, radius, lengthening, prolongation, production, protraction, tension, tensure, extension, line, nail, inch, hand, palm, foot, cubit, yard, ell, fathom, rood, pole, furlong, mile, league, chain, link, arpent, handbreadth, jornada, kos, vara, astronomical unit, AU, light- year, parsec, nanometer, nm, micron, micrometer, millimicron, millimeter, mm, centimeter, cm, meter, kilometer, km, pedometer, perambulator, scale, long, longsome, lengthy, wiredrawn, outstretched, lengthened, sesquipedalian, interminable, no end of, macrocolous, linear, lineal, longitudinal, oblong, as long as my arm, as long as today and tomorrow, unshortened &c (shorten), lengthwise, at length, longitudinally, endlong, along, tandem, in a line, in perspective, from end to end, from stem to stern, from head to foot, from the crown of the head to the sole of the foot, from top to toe, fore and aft.

For further exploring for "kilometer" in Webster Dictionary Online