something that kills weeds; spec. any of numerous chemical preparations used to kill weeds (= herbicide, n. b); material of this kind; also figurative…

Something that kills or (in early use) suppresses the growth of weeds; spec. a chemical weedkiller or herbicide.

†(a) Proprietary name for a preparation, probably of sodium arsenite, used as a weed-killer. Obsolete. (b) Any chemical agent that is toxic to some…

Something that kills algae; spec. a preparation used for this purpose.

= algicide, n.

A substance for destroying pests, esp. insects. Also (occasionally): a herbicide. Also figurative.

a selective herbicide used esp. for controlling brushwood; 2,4,5-trichlorophenoxyacetic acid, C6H2Cl3·O·CH2COOH.

A substance that kills trees.

A selective herbicide used against perennial grasses, usually as the water-soluble sodium salt; 2,2-dichloropropionic acid, CH3CCl2COOH.

A hormone weedkiller that is also effective against some woody plants; 2-(2,4,5-trichlorophenoxy)propionic acid.

A sterilizing agent. An agent used to make something free of plant life or micro-organisms; a herbicide or disinfectant.

A triazine herbicide employed against annual grasses and broad-leaved weeds.

A selective herbicide, used alone and with other herbicides, esp. to control weeds of cereal crops and grassland…

A selective agricultural herbicide which has been used chiefly for pre-emergence control of broadleaf weeds and annual grasses.

A quaternary compound with herbicidal properties (see quot. 1960).

trichloroacetic acid (a herbicide).

A derivative of picolinic acid used as a herbicide and defoliant against deep-rooted weeds and woody plants; 4-amino-3,5,6-trichloropicolinic…

A herbicide used to control grasses and other weeds in a wide variety of crops.