1.  ulceration(n = noun.state) ulcer - a circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in necrosis of tissue;
is a kind of lesion
has particulars: aphthous ulcer, bedsore, decubitus ulcer, pressure sore, chancroid, peptic ulcer, peptic ulceration, canker, canker sore, noli-me-tangere, noma

2.  ulceration(n = noun.process) - the process of ulcer formation; the process of becoming ulcerated;
is a kind of biological process, organic process
Derived form verb ulcerate₁

   The process of forming an ulcer, or of becoming ulcerous; the state of being ulcerated; also, an ulcer. [1913 Webster]

peptic ulceration