ulceration vs ulcer

ulceration and ulcer both are nouns.

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

As nouns, ulceration and ulcer are synonyms defined as:

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

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