witness mark
n.— «When recovering evidence for further observation, preservation of any dirt or grease mark on samples can be vital if critical evidence of its past history is not to be lost. Such trace evidence (witness marks) can help in reconstructing past movements of the sample, such as contact with older, perhaps mating parts.» —by Peter Rhys Lewis, Ken Reynolds, Colin Gagg Forensic Materials Engineering: Case Studies Sept. 29, 2003. (source: Double-Tongued Dictionary)
Further reading
A writer stumbles upon a tiny, motionless creature on a country road and, against all good advice, takes it home. The resulting memoir, Raising Hare, is a lovely meditation on nature and our relationship to it. And: have you ever invented a fake...
Chase from Jacksonville, Florida, grew up in Sacramento, California, where kids played Rochambeau instead of rock, paper, scissors. Why the difference in names? Nobody knows. Folklorists call this a choosing game, and while the hand-game itself...