'Wacke' definitions:

Definition of 'Wacke'

From: GCIDE

Wacke \Wack"e\, Wacky \Wack"y\, n. [G. wacke, MHG. wacke a large stone, OHG. waggo a pebble.] (Geol.) A soft, earthy, dark-colored rock or clay derived from the alteration of basalt. [1913 Webster]