The American Heritage® Dictionary of the English Language, 4th Edition
n. An annual weed (Sinapis arvensis) in the mustard family, native to Eurasia and naturalized in North America, having racemes of yellow flowers and hairy stems and foliage.
n. Any of several yellow-flowered cruciferous weeds of grain fields, especially wild mustard.
the GNU version of the Collaborative International Dictionary of English
n. A cruciferous plant (Brassica sinapistrum) with yellow flowers; wild mustard. It is troublesome in grain fields. Called also chardock, chardlock, chedlock, and kedlock.
The Century Dictionary and Cyclopedia
n. A common name of the wild mustard, Brassica Sinapistrum, a common pest in grain-fields. Also written carlick.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. weedy Eurasian plant often a pest in grain fields
Word Usage
"Such dry waste places send up plants to flower, such as charlock and poppy, quicker than happens in better soil, but they do not reach nearly the height or size."