Definition of: canker

(kang′kər) noun
1. Pathol. Any ulcer with a tendency to gangrene; a group of small ulcers in the mouth.
2. A disease of fruit trees.
3. Any secret or spreading evil.
4. A disease affecting the feet of horses, characterized by the discharge of an evil–smelling exudate.
5. An inflammation of the external ear in cats and dogs.
6. The cankerworm.
7. Obs. The dog rose; also canker blossom.
—v.t.
1. To infect with canker.
2. To eat away or into like a canker; corrode; corrupt.
—v.t.
3. To fester with or be attacked by a canker. [<AF cancre <L cancer crab, ulcer]