char·lock /ˈʧɑrˌlɑk, lək/
  野芥子
  Char·lock n.  Bot. A cruciferous plant (Brassica sinapistrum) with yellow flowers; wild mustard. It is troublesome in grain fields. Called also chardock, chardlock, chedlock, and kedlock.
  Jointed charlock, White charlock, a troublesome weed (Raphanus Raphanistrum) with straw-colored, whitish, or purplish flowers, and jointed pods: wild radish.
  ◄ ►
  charlock
       n : weedy Eurasian plant often a pest in grain fields [syn: field
           mustard, wild mustard, chadlock, Brassica kaber, Sinapis
           arvensis]