The Collaborative International Dictionary of English v.0.48:
Cockle \Coc"kle\ (k[o^]k"k'l), n. [OE. cockes cockles, AS.
s[=ae]coccas sea cockles, prob, from Celtic; cf. W. cocs
cockles, Gael. cochull husk. Perh. influenced by F. coquille
shell, a dim. from the root of E. conch. Cf. Coach.]
1. (Zool.) A bivalve mollusk, with radiating ribs, of the
genus Cardium, especially Cardium edule, used in
Europe for food; -- sometimes applied to similar shells of
other genera.
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2. A cockleshell.
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3. The mineral black tourmaline or schorl; -- so called by
the Cornish miners. --Raymond.
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4. The fire chamber of a furnace. [Eng.] --Knight.
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5. A hop-drying kiln; an oast. --Knight.
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6. The dome of a heating furnace. --Knight.
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Cockle hat, a hat ornamented with a cockleshell, the badge
of a pilgrim. --Shak.
Cockle stairs, winding or spiral stairs.
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