K
Abbreviation with 9 meanings
| Stands for | Kilo- (thousand) |
|---|---|
| Meanings | 9 |
| Categories | Units & Measurements, Science & Engineering, Texting & Internet Slang, Sports, Arts & Entertainment |
| Also written | k, K. |
K has nine meanings. The most common are Kilo- (thousand) (metric and SI unit) and Thousand (math); it can also stand for Potassium, Okay, Strikeout, Karat and Kelvin, plus 2 more listed below.
Meanings of K at a glance
| # | K stands for | Context |
|---|---|---|
| 1 | Kilo- (thousand) | Units & Measurements › Metric and SI Unit |
| 2 | Thousand | Units & Measurements › Math |
| 3 | Potassium | Science & Engineering › Chemical Element |
| 4 | Okay | Texting & Internet Slang › Texting and Chat |
| 5 | Strikeout | Sports › Baseball |
| 6 | Karat | Units & Measurements › Metric and SI Unit |
| 7 | Kelvin | Units & Measurements › Engineering Unit |
| 8 | Kicker | Sports › American Football |
| 9 | Köchel catalogue number | Arts & Entertainment › Music |
1. Kilo- (thousand) (k)
Units & Measurements · Metric and SI Unit Abbreviations
The thousand multiplier, 10^3, and the most widely used metric prefix in daily life: kilometer, kilogram, kilowatt and kilobyte. Correct SI usage requires a lowercase k, which keeps it distinct from capital K for the kelvin.
Example: A 1.5 kW space heater draws about 12.5 amps on a 120-volt circuit.
From Greek chilioi, thousand, it was one of the original prefixes of the French metric system of 1795. Writing Kg or Km is a common error. Computing long used K loosely for 1,024, which led the IEC to introduce the binary prefix Ki (kibi-) in 1998. In casual English a lone k means thousand, as in a $60k salary.
2. Thousand
Units & Measurements · Math Abbreviations
Shorthand for thousand in salaries, prices, social media follower counts and mileage, borrowed from the metric prefix kilo-. A $75K salary means $75,000, and 12K followers means about twelve thousand.
Example: Remote marketing manager role, $95K to $110K plus bonus.
The capital K is informal; the metric prefix itself is lowercase k. In finance, K for thousand competes with the older M (from Roman numerals), which causes confusion. Y2K used K for thousand to denote the year 2000, and race names such as 5K and 10K mean kilometers.
3. Potassium
Science & Engineering · Chemical Element Abbreviations · also used in medicine
Potassium is element 19, a soft alkali metal that reacts with water vigorously enough to ignite the released hydrogen with a lilac flame. Potassium ions are vital for nerve impulses and heart rhythm, bananas and potatoes are rich dietary sources, and potash fertilizers supply the K in N-P-K ratings.
Example: The mine ships muriate of potash grading 60% K2O to fertilizer blenders.
Humphry Davy isolated potassium in 1807 by electrolysis of molten caustic potash, the first metal obtained that way. Its symbol K comes from the Neo-Latin kalium, derived from Arabic al-qali (plant ashes), the same root as "alkali"; German still calls it Kalium. The English name comes from potash, the residue from leaching wood ashes in pots. Do not confuse it with K for kelvin.
4. Okay
Texting & Internet Slang · Texting and Chat Abbreviations
One-letter acknowledgment meaning "okay," the shortest possible reply in a text conversation. It confirms receipt of a message but, used alone, often reads as curt, bored or annoyed.
Example: K, I'll pick up milk on the way home tonight.
A lone "k," especially with a period ("k."), is widely perceived as passive-aggressive or cold, which is why many texters write "kk," "okay" or "ok!" instead. Among close friends it can be perfectly neutral. Avoid it in professional replies, where it can seem dismissive.
5. Strikeout
Sports · Baseball Abbreviations
Out recorded when a batter gets three strikes, by swinging and missing, taking a pitch in the strike zone or fouling off a two-strike bunt. Scorers write a backward K for a called third strike.
Example: The ace struck out 13, including a K of the cleanup hitter on three pitches.
Nineteenth-century scorer Henry Chadwick used K, the prominent last letter of "struck", because S was taken by sacrifice. Box scores also write SO. Nolan Ryan holds the career record with 5,714 strikeouts. Fans hang "K" signs in the stands to count a pitcher's strikeouts. In football K means kicker.
6. Karat
Units & Measurements · Metric and SI Unit Abbreviations
A measure of gold purity in 24ths: 24K is pure gold, 18K is 75 percent, 14K is 58.3 percent and 10K, the US legal minimum for jewelry sold as gold, is 41.7 percent. It is stamped inside rings, on clasps and on watch cases.
Example: The chain is stamped 14K, so it is just over half pure gold.
Also written kt or k, as in 18kt. Much of Europe stamps purity in thousandths instead: 750 for 18K, 585 for 14K and 375 for 9K, the lowest standard hallmarked in the UK. Karat and carat share a root, Greek keration (carob seed); American English uses karat for purity to keep it apart from gem weight.
7. Kelvin
Units & Measurements · Engineering Unit Abbreviations
The SI base unit of temperature, counted from absolute zero, the coldest possible temperature. Water freezes at 273.15 K, and kelvins take no degree sign. Lighting uses the same unit for color temperature, from about 2700 K (warm white) to 6500 K (daylight).
Example: Choose 3000 K bulbs for a warm feel in the living room and 4000 K for the kitchen.
Named after William Thomson, Lord Kelvin, who proposed an absolute temperature scale in 1848. Since 1968 the unit has been "kelvin" rather than "degree Kelvin", and since 2019 it is defined by fixing the Boltzmann constant. A change of 1 K equals a change of 1°C. Capital K must not be confused with lowercase k, the kilo- prefix.
8. Kicker
Sports · American Football Abbreviations
Specialist who kicks field goals, extra points and kickoffs. Field goals are kicked from a teammate's hold about seven yards behind the line of scrimmage, so the attempt is roughly 17 yards longer than the distance from the line to the goal line.
Example: The K hit from 58 yards on the final play to send the game to overtime.
Almost all modern kickers approach soccer-style from the side; Mark Moseley, who retired in 1986, was the last full-time straight-on kicker in the NFL. Kickers are among the few players who often play into their forties. In baseball box scores K means strikeout instead.
9. Köchel catalogue number (K.)
Arts & Entertainment · Music Abbreviations
Number identifying a work by Wolfgang Amadeus Mozart in the chronological catalog compiled by Ludwig von Köchel, as in Eine kleine Nachtmusik, K. 525. Also written KV (Köchel-Verzeichnis).
Example: Tonight's program opens with the Piano Concerto No. 21, K. 467.
Köchel published the first edition in 1862, numbering 626 works up to the Requiem, K. 626. Later revisions renumbered some works, so older recordings may show different numbers. In baseball scoring K means strikeout.
Related abbreviations
More metric and SI unit abbreviations
- Gy – Gray
- h – Hecto- (hundred)
- ha – Hectare
- hL – Hectoliter
- kat – Katal
- kg – Kilogram
- km – Kilometer
- km² – Square kilometer
See all 64 metric and SI unit abbreviations →