The term "secondary reading" covers more or less the same meaning as the term "error" in textual criticism, but may be preferred to it for reasons of clarity.
Any variant reading used for the purpose of classification of a textual tradition should be polarised: if on a certain variant location there are two variant readings A and B, one of them should be the primary reading (the original or ancestral reading) and the other the secondary reading (the error). This terminology is influenced by cladistics and is less vague than the traditional terminology used in textual criticism. Contrary to the term "error", the term "secondary reading" is not absolute, but relative: reading B can be secondary vis-à-vis reading A, but primary vis-à-vis reading C. In addition, not all secondary readings are linguistic mistakes, a correction can be a secondary reading, indeed any type of change (or innovation) can be a secondary reading.
In other languages
DE: sekundäre Lesart
FR: leçon secondaire
IT: lezione secondaria