my layman understanding, a real statistician will surely intervene.

standard deviation is a measure that informs about the distribution. A high standard deviation means a "wide bell curve". A low standard deviation means that all values are closely clustered around the middle of the curve.

So if your value is 2 x standard deviation (for example) that means it is a relatively rare outlier, since 2 x standard deviation covers 95% of the bell curve. In particle physics I believe they require 5 standard deviations to confirm an observation.