witness-mark
n.— «Wherever you wanted to cut off, the valve gear could e put at that notch or clamped at that place, which will bring the “cut-off” witness mark right for cutting off.» —by Robert Grimshaw Supplement to the Steam Engine Catechism (New York) , 1888. (source: Double-Tongued Dictionary)
Further reading
Enthusiastic book recommendations! Martha’s savoring the biography of Alexander von Humboldt, the 19th-century explorer, polymath, and naturalist who revolutionized our understanding of nature and predicted the effects of human activity on...
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...