Wiktionary
n. (context statistics English) A measure of how likely a mean of means is to be wrong. It is the standard deviation of the sample sizes in each to the sample means.
Wikipedia
The standard error (SE) is the standard deviation of the sampling distribution of a statistic, most commonly of the mean. The term may also be used to refer to an estimate of that standard deviation, derived from a particular sample used to compute the estimate.
For example, the sample mean is the usual estimator of a population mean. However, different samples drawn from that same population would in general have different values of the sample mean, so there is a distribution of sampled means (with its own mean and variance). The standard error of the mean (SEM) (i.e., of using the sample mean as a method of estimating the population mean) is the standard deviation of those sample means over all possible samples (of a given size) drawn from the population. Secondly, the standard error of the mean can refer to an estimate of that standard deviation, computed from the sample of data being analyzed at the time.
In regression analysis, the term "standard error" is also used in the phrase standard error of the regression to mean the ordinary least squares estimate of the standard deviation of the underlying errors.
Usage examples of "standard error".
Weve found an absolute age of two-point-four times ten-to-the-ninth years with the standard error deviation.
In fact Pat had worked out a simple way to cheat when our teacher, with a tired lack of anger, split us up and made us run tests only with other people-whereupon our scores dropped to the limits of standard error.
It was a hellish long way, and the standard error of arrival location accordingly large.