Shale

Part of speech: noun (n.)

1. A shell or husk; a cod or pod. "The green shales of a bean." Chapman.

2. A fine-grained sedimentary rock of a thin, laminated, and often friable, structure. Bituminous shale. See under Bituminous.

Part of speech: verb (v.)

To take off the shell or coat of; to shell. Life, in its upper grades, was bursting its shell, or was shaling off its husk. I. Taylor.