口内炎 /kǒunèiyán/ angolul

aphthous ulcer▼(ulcer in the mouth caused by break in mucous membrane)
noun

stomatitis [stomatitides]▼(inflammation of parts of the mucous membrane that lines the mouth)
noun
[UK: ˌstɒ.mə.ˈtaɪ.tɪs] [US: ˌstoʊ.mə.ˈtaɪ.tɪs]