A set of brief descriptive coefficients that summarizes a given data set that represents either the entire population or a sample. The measures that describe the data set are measures of central tendency and measures of variability or dispersion. Measures of central tendency include the mean, median and mode, while measures of variability include namely the standard deviation and the variance.

It is any process or condition external to the natural physiology of living organisms that results in the sudden mortality of biomass in a community on a time scale significantly shorter than that of the accumulation of the biomass.

In Behavioural Ecology it is the social status of an animal within a group; an individual that maintains high social status by aggressive behaviour towards others is exhibiting dominance.  In Vegetation studies dominance refers to the capacity for one species to exert overriding influence upon others within the community.