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
The words tough, through, and dough all end in O-U-G-H. So why don’t they rhyme? A lively new book addresses the many quirks of English by explaining the history of words and phrases. And: have you ever been in a situation where a group makes...
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...