witness mark
n.— «The laminations can be designed to accommodate flipping, or alternation as noted above, to average out asymmetries. The design should incorporate a “witness mark” so that the pattern of alternation is evident.» —by Alexander Wu Choo, Maruy Tigner Handbook of Accelerator Physics and Engineering Mar. 26, 1999. (source: Double-Tongued Dictionary)
Further reading
Astronauts returning from space say they experience what’s called the overview effect, a new understanding of the fragility of our planet and our need to reflect on what humans all share as a species. A book about the end of the universe...
One of the most powerful words you’ll ever hear — and one of the most poignant — isn’t in dictionaries yet. But it probably will be one day. The word is endling, and it means “the last surviving member of a species.” The...