shoulder peak
n.— «With better forward-planning and more experimentation, those early successes can perhaps be consolidated with a wider range of programmes into “shoulder peak” as 11 o’clock is now fashionably known. » —“Was it worth it?” Guardian (U.K.) July 12, 1999. (source: Double-Tongued Dictionary)
Further reading
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...