Can·ker n.
1. A corroding or sloughing ulcer; esp. a spreading gangrenous ulcer or collection of ulcers in or about the mouth; -- called also water canker, canker of the mouth, and noma.
2. Anything which corrodes, corrupts, or destroy.
The cankers of envy and faction. --Temple.
3. Hort. A disease incident to trees, causing the bark to rot and fall off.
4. Far. 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.
5. A kind of wild, worthless rose; the dog-rose.
To put down Richard, that sweet lovely rose.
And plant this thorm, this canker, Bolingbroke. --Shak.
Black canker. See under Black.