km
Abbreviation with 4 meanings
| Stands for | Kilometer |
|---|---|
| Meanings | 4 |
| Categories | Units & Measurements, Medical, Science & Engineering, Geography & Places |
| Also written | KM, Km |
km has four meanings. The most common are Kilometer (metric and SI unit) and Kaplan-Meier (estimator) (medical research); it can also stand for Michaelis constant and Comoros.
Meanings of km at a glance
| # | km stands for | Context |
|---|---|---|
| 1 | Kilometer | Units & Measurements › Metric and SI Unit |
| 2 | Kaplan-Meier (estimator) | Medical › Medical Research |
| 3 | Michaelis constant | Science & Engineering › Biology |
| 4 | Comoros | Geography & Places › Country Code |
1. Kilometer
Units & Measurements · Metric and SI Unit Abbreviations
One thousand meters, about 0.621 mile, the standard unit for road distances, speed limits and running races in metric countries. A 5K race is 5 km and a marathon is 42.195 km.
Example: The next rest area is 38 km ahead on the A7.
Two pronunciations are accepted in American dictionaries, "KILL-o-mee-ter" and "kil-OM-i-ter"; metrologists prefer the first because it parallels kilogram. For a quick mental conversion, multiply km by 0.6 for an approximate mile figure, or by 5/8 for a closer one. The symbol is km, never Km or KM, and it is not pluralized: 10 km, not 10 kms.
2. Kaplan-Meier (estimator) (KM)
Medical · Medical Research Abbreviations
Statistical method for estimating survival over time from data in which some participants have not had the event when the study ends or leave early (censored data). Kaplan-Meier curves are the stepped survival graphs seen in most oncology and cardiology trial reports.
Example: KM curves separated after six months and stayed apart through year five.
Published by Edward Kaplan and Paul Meier in 1958, the paper became one of the most cited in statistics. Curves are usually compared with the log-rank test, and tick marks show censored participants. Estimates at the far right of a curve are imprecise because few people remain at risk.
3. Michaelis constant (Km)
Science & Engineering · Biology Abbreviations
In enzyme kinetics, the substrate concentration at which a reaction proceeds at half its maximum rate (Vmax). A low Km means the enzyme reaches high activity even at low substrate levels, often described as high affinity.
Example: Hexokinase has a Km for glucose far lower than glucokinase does, so it works at low blood sugar.
Named after Leonor Michaelis and Maud Menten, who published their rate equation in 1913. The value is written with a subscript m. Lineweaver-Burk plots were long used to estimate Km and Vmax, though nonlinear fitting is now preferred. Do not confuse it with km, the symbol for kilometer.
4. Comoros (KM)
Geography & Places · Country Code Abbreviations
Volcanic island nation between Mozambique and Madagascar, with Moroni as its capital. Its code comes from Komori, and its alpha-3 code, COM, looks like the .com domain.
Example: Vanilla and ylang-ylang exports from KM supply perfume makers in France.
Comoros claims Mayotte, which voted to remain French. In lowercase km means kilometre, and km is also the language code for Khmer.
Related abbreviations
More metric and SI unit abbreviations
- hL – Hectoliter
- k – Kilo- (thousand)
- kat – Katal
- kg – Kilogram
- km² – Square kilometer
- kN – Kilonewton
- kt – Kiloton (TNT equivalent)
- L – Liter
See all 64 metric and SI unit abbreviations →
More medical research abbreviations
- IIT – Investigator-initiated trial
- IQR – Interquartile range
- IRB – Institutional review board
- ITT – Intention-to-treat
- LOE – Level of evidence
- LR – Likelihood ratio
- LTFU – Lost to follow-up
- MA – Meta-analysis
See all 94 medical research abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.