A character (such as a reading in a witness, or a position in a DNA or protein sequence) that allows two members of a dataset to be grouped to the exclusion of others is called "parsimoniously informative". The character must exist in at least two different states, each of which is shared by at least two witnesses. Thus if witnesses A and B share the same reading and C and D share a different reading, the reading is informative under the principle of maximum parsimony in grouping A and B to the exclusion of C and D. However, if C and D each had different readings, the character would not be informative.
In other languages
DE: parsimonisch informativ, or the English term
FR: parcimonieusement informatif
IT: parsimoniosamente informativo