from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A soft, earthy, dark-coloured rock or clay derived from the alteration of basalt.
from the GNU version of the Collaborative International Dictionary of English
- n. A soft, earthy, dark-colored rock or clay derived from the alteration of basalt.
from The Century Dictionary and Cyclopedia
- n. A soft homogeneous clay arising from the decomposition of some form of volcanic or eruptive rock. It is of a greenish or brownish color. Compare graywacke.
Middle High German wacke "boulder," from Old High German waggo or wacko, yielding German Wacke, probably cognate with Old High German wegan "to move" (Wiktionary)