bright line
n.— «“Bright lines,” as in “bright-line rule,” meaning a clear, unambiguous standard, are in demand in other contexts as well.» —“Bright lines and the search for certainty” by Ruth Walker Christian Science Monitor (Boston, Mass.) Dec. 15, 2005. (source: Double-Tongued Dictionary)
Further reading
In Cockney rhyming slang, apples and pears is a synonym for “stairs,” and dustbin lids means kids. Plus, sniglets are clever coinages for things we don’t already have words for. Any guesses what incogsneeto means? It’s the...
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...