[ki-lom-i-ter, kil-uh-mee‑] 
| a unit of length, the common measure of distances equal to 1000 meters, and equivalent to 3280.8 feet or 0.621 mile. Abbreviation: km |
[kil-uh-me-trik] , kil⋅o⋅met⋅ri⋅cal, adjective [kil-uh-mee-ter] has been used since the early 1800's. A second pronunciation: [ki-lom-i-ter], with stress on the second syllable only, was first recorded in America before 1830. Although often criticized on the basis of analogy, this pronunciation has persisted in American English, increasing in frequency, and has gained popularity in British English as well. It is reinforced by words for instruments (rather than units) of measurement ending in -meter, as thermometer, barometer, and speedometer, having stress on the -om syllable. Both pronunciations are used by educated speakers, including members of the scientific community.| kil·o·me·ter (kĭ-lŏm'ĭ-tər, kĭl'ə-mē'tər) n. Abbr. km A metric unit of length equal to 1,000 meters (0.62 mile). See Table at measurement. kil'o·met'ric (kĭl'ə-mět'rĭk) adj. Usage Note: Although the pronunciation of kilometer with stress on the second syllable, (kĭ-lŏm'ĭ-tər), is often censured because it does not conform to the stress pattern in millimeter and centimeter (it originally came about by false analogy with barometer and thermometer), it continues to thrive in American English. In a recent survey, 69 percent of the Usage Panel preferred this pronunciation, while 29 percent preferred the pronunciation (kĭl'ə-mē'tər). |
In the metric system, one thousand meters, or about five-eighths of a mile.