Thousand

Thousand is the cardinal number equal to 1,000, representing ten cubed in the base-10 numeral system. It is written as 1,000 in most modern notations and as M in Roman numerals. The term derives from Old English thūsend, from Proto-Germanic *þūsundaz, with cognates in Dutch duizend and German tausend. The related SI prefix kilo- denotes a factor of one thousand, from the Greek khilioi; it is used in units such as kilogram, kilometer, and kilobyte.

In mathematics and everyday use, a thousand commonly marks a large, approximate quantity (e.g., thousands of people). The word can form compounds such as thousandfold (multiplied by a thousand) or thousandth (the ordinal form or the fractional value 1/1000). Families of numbers show progression from hundred to thousand to million.

In historical and cultural contexts, thousands have been used as administrative or military units in some societies, and the term appears in phrases like a thousand and one nights and other idioms. The plural thousands is used when referring to multiple thousands of items.

In language, many languages have distinct words for 1,000 or use the same root; e.g., mille (French), mil (Spanish and Portuguese), tausend (German), thousand (English).