A Bucket Error is when multiple different concepts or variables are incorrectly lumped together in one's mind as a single concept/variable, potentially leading to distortions of one's thinking. Bucket Errors are related to Fallacies of Compression.
The term, Bucket Error, was introduced in "Flinching away from truth” is often about *protecting* the epistemology where an example is given of a child who refuses to believe that they made a spelling mistake. The child is unwilling to believe this fact because they believe having made a spelling mistake is incompatible with becoming a writer which is their dream. "Becoming a writer" and "never making spelling mistakes" are lumped in the same bucket despite in fact being separate variables.