What is Confidence interval?

A range of values calculated from sample data to estimate an unknown indicator of the population (say, the mean). Instead of a single number (a point estimate), a "lower limit – upper limit" is given, together with a confidence level (for example, 95%). 95% means that if samples were drawn many times by this method and an interval calculated each time, about 95% of them would contain the true value. As the sample gets larger, the interval narrows, that is, the estimate becomes more precise.

Source: Britannica: Confidence interval; Britannica: Point estimation