ulcer vs ulceration

ulcer and ulceration both are nouns.

Word	Noun	Adjective	Verb	Adverb
ulcer	Yes	No	No	No
ulceration	Yes	No	No	No

As nouns, ulcer and ulceration are synonyms defined as:

ulcer and ulceration: a circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in necrosis of tissue

ulcer (noun)	ulceration (noun)
a circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in necrosis of tissue	the process of ulcer formation; the process of becoming ulcerated
	a circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in necrosis of tissue