witness mark
n.— «With a rule draw out a witness mark from each saw cut on the surfaced side of the line boards and plainly write there-on a brief designation of what line of the building the saw cut is on, as “Brick Line.”» —by Joseph Baker Davis Surveying for Beginners (Ann Arbor, Michigan) , 1909. (source: Double-Tongued Dictionary)
Further reading
Mary Beth in Greenville, South Carolina, wonders: Why do we say four-oh-nine for the number 409 instead of four-zero-nine or four-aught-nine? What are the rules for saying either zero or oh or aught or ought to indicate that arithmetical symbol...
It’s hard to imagine now, but there was a time when people disagreed over the best word to use when answering the phone. Alexander Graham Bell suggested answering with ahoy! but Thomas Edison was partial to hello! A fascinating new book about...