Word Study
lambkill
CIDE DICTIONARY
lambkill, n.
A small American ericaceous shrub (Kalmia angustifolia ), resembling mountain laurel but having narrower leaves and small red flowers; -- called also calfkill , sheepkill , sheep laurel , etc. It is supposed to poison young sheep and other animals that eat it at times when the snow is deep and they cannot find other food. [Webster 1913 Suppl.]
For further exploring for "lambkill" in Webster Dictionary Online