Canker meaning : A plant disease marked by gradual decay. A region of dead plant tissue caused by such a disease. A worm or grub that destroys plant buds or leaves; cankerworm. A corroding or sloughing ulcer; especially a spreading gangrenous ulcer or collection of ulcers in or about the mouth. Anything which corrodes, corrupts, or destroys. A kind of wild rose; the dog rose. An obstinate and often incurable disease of a horse's foot, characterized by separation of the horny portion and the development of fungoid growths. Usually resulting from neglected thrush. An avian disease affecting doves, poultry, parrots and birds of prey, caused by Trichomonas gallinae.