What does "cockle" mean?

Additional senses

1. 2.The mineral black tourmaline or schorl; -- so called by the Cornish miners. Raymond.
2. 3.The fire chamber of a furnace. [Eng.] Knight.
3. 4.A hop-drying kiln; an oast. Knight.
4. 5.The dome of a heating furnace. Knight. Cockle hat, a hat ornamented with a cockleshell, the badge of a pilgrim. Shak. -- Cockle stairs, winding or spiral stairs.
5. 6.To cause to contract into wrinkles or ridges, as some kinds of cloth after a wetting. Cockling sea, waves dashing against each other with a short and quick motion. Ham. Nav. Encyc.
6. 7.(a) A plant or weed that grows among grain; the corn rose (Luchnis Githage). (b) The Lotium, or darnel.