Water-hemlock, a plant whose root is poisonous. This term was used by the ancients and by medical writers for the Conium maculatum, or common hemlock, the expressed juice of which was used as a common poison. Socrates and Phocion perished by it. It is now used medicinally in moderate doses, with good effect.

a genus of poisonous umbelliferous plants, of which the water hemlock or cowbane is best known.