kS

Ks is an abbreviation that occurs in multiple disciplines and can refer to different concepts depending on the context. Common usages include a time unit, an infrared photometric band, a molecular-evolution metric, and a statistical test.

Kilosecond, abbreviated ks or ks, equals 1,000 seconds (about 16 minutes 40 seconds). It is used in astronomy and other contexts to express exposure times and observing durations.

In astronomy, the Ks band, or K-short band (K_s), is a near-infrared photometric filter centered near 2.15 micrometres. It is designed to reduce thermal background compared with the standard K band and is widely used for imaging and photometry of stars and galaxies in the infrared.

K_s denotes the rate of synonymous substitutions per synonymous site between two DNA sequences. Used to estimate divergence times and to study gene duplications, K_s is often compared with K_a (nonsynonymous substitutions) and interpreted within the Ka/K_s framework of selective constraint.

The Kolmogorov–Smirnov test (KS test) is a nonparametric method for comparing distributions. It uses the D statistic to quantify the maximum distance between empirical distribution functions, yielding a P-value to assess similarity between a sample and a reference distribution or between two samples.

Capitalization matters: KS (uppercase) commonly denotes the state of Kansas, a separate usage from Ks or K_s.