n. 1. One that lives or is located outside or at the edge of a given area: outliers of the forest standing in the field. 2. One that exists outside or at an extreme of a category, pattern, or expectation; an extreme case or exception: "those egg-laying outliers of mammaldom, the duck-billed platypus and the anteating echidna" (Natalie Angier). 3. A value far from most others in a set of data: "Outliers make statistical analyses difficult" (Harvey Motulsky). 4. A portion of stratified rock separated from a main formation by erosion. |
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