Wolf
A wolf refers to a noticeably out-of-tune interval in a given tuning system that results from adjusting or "tempering" that interval to fit within a fixed number of notes. For example, in order to fit the 12 fifths of Pythagorean tuningPythagorean tuning is an approach to tuning based on stacking pure fifths (i.e. fifths with an exact frequency ratio of 2:3).Visit the link to learn more into seven octaves, one of the fifths needs to be significantly flat.
Context
Introduction to European historical tunings and temperaments, 12 Henricus Grammateus, 12 Tertial-Quintal (Erlanger Traktat)