The letter "K" is commonly used to indicate 1,000 when dealing with certain numeric situations, especially money. While not always professionally recognized, the use of the letter "K" has become widely used in mainstream society.
Utilizing the letter "K" appropriately resembles adding a unit to a number or set. For example, "1K" is the equivalent of $1,000 and "200K" is shorthand for $200,000. This can also be utilized with uneven values, such as "1.5K" serving as a shortened form of $1,500. While typically an uppercase "K" is utilized for this type of abbreviation, lowercase variations can also be used interchangeably.