[1920–25; kilo- + parsec]This word is first recorded in the period 1920–25. Other words that entered Englishat around the same time include: Unknown Soldier, audio, ski jump, tie-in, zipperkilo- is a Greek combining form meaning “thousand,” introduced from French in the nomenclatureof the metric system (kiloliter). On this model, kilo- is used in the formation of compound words in other systems of measurement (kilowatt). Other words that use the affix kilo- include: kilocycle, kilogauss, kilohertz, kilomegacycle, kiloton