General Science

  • prefix
    (written as kilo-)
    1024 units, equal to 210.


  • prefix
    (written as kilo-)
    one thousand, 103.


  • prefix 1,024 units, equal to 210
  • symbolK


  • (written as kilo-)
    A metric prefix representing 103, which is equal to a thousand. For instance, 1 kilohertz is equal to 103 Hz. When referring to binary quantities, such as bits and bytes, it is equal to 210, or 1,024, although this is frequently rounded to 1,000. To avoid any confusion, the prefix kibi- may be used when dealing with binary quantities. Its proper abbreviation is k, although K is often used.

Media Studies

  • noun
    (written as Kilo)
    an internationally recognised code word for the letter K, used in radio communications



  • noun a measure of weight equalling one thousand grams

Origin & History of “kilo”

Khílioi was Greek for a ‘thousand’. It was adopted in French in the 1790s as the prefix for ‘thousand’ in expressions of quantity under the new metric system, and various compound forms (kilogram, kilolitre, kilometre, etc) began to find their way into English from the first decade of the 19th century onwards. The first recorded instance of kilo being used in English for kilogram dates from 1870.