canker sore vs. ulcer

canker sore

noun

1. an ulceration of a mucous membrane, especially of the mouth.

ulcer

[ uhl-ser ]show ipa

noun

1. a sore on the skin or a mucous membrane, accompanied by the disintegration of tissue, the formation of pus, etc.
2. peptic ulcer.
3. any chronically corrupting or disrupting condition, element, etc.