U

fiddlehead

noun

Nautical. a billethead having a form similar to the volute carved at the upper end of a violin.
the young, coiled frond of various species of ferns, eaten as a vegetable.

noun

nautical an ornamental carving, in the shape of the scroll at the head end of a fiddle, fitted to the top of the stem or cutwater
US and Canadian the edible coiled tip of a young fern frond

“one with a head as hollow as a fiddle,” 1854 (fiddleheaded), from fiddle (n.) + head (n.). As a name for young fern fronds, from 1882, from resemblance to a violin’s scroll.