topknot, bun, coiled hairknot
髱 centers on hair tied up into a rounded knot on the head: a topknot, bun, or coiled hairknot.
髱 combines 髟 (hair) with 包 (wrap), suggesting hair wrapped or coiled into a knot. The exact historical development is uncertain, but the component structure fits the meaning.
The top part 髟 represents long hair, and the bottom part 包 means wrap. Picture wrapping long hair into a tight bun on top of the head.
For ホウ, imagine a hair bun shaped like a perfect circle, and think of the English word 'whole' (ホウ) — the bun is a whole, coiled knot.