unk-unk
n.— «Many unknowns are evident at the beginning, and may be called “known unknowns.” These are identified early as potential problem areas and are therefore singled out for examination and resolution.…However, many other problem areas are only identified later when they are discovered during system development. These unanticipated problems are often identified as “unknown unknowns” are “unk-unks” to distinguish them from the group of “known unknowns” that were recognized at the outset and dealt with.» —by Alexander Kossiakoff Systems Engineering Nov. 15, 2002. (source: Double-Tongued Dictionary)
Further reading
Book recommendations and the art of apology. Martha and Grant share some good reads, including an opinionated romp through English grammar, a Spanish-language adventure novel, an account of 19th-century dictionary wars, and a gorgeously illustrated...
A stereotype is a preconceived notion about a person or group. Originally, though, the word stereotype referred to a printing device used to produce lots of identical copies. • The link between tiny mythical creatures called trolls and modern-day...