[¦thrē ə¦mē·nō ¦tü ¦fīv dī‚klȯr·ə‚ben¦zō·ik ′as·əd] (organic chemistry) C7H5O2-NCl2 A white solid with a melting point of 200-201°C; solubility in water is 700 parts per million at 20°C; used as a preemergence herbicide for soybeans, corn, and sweet potatoes.