pieces of soft tissue at the back of the nose and throat, which are part of the body's immune system and can swell up and cause breathing difficulties, especially in children
NAmE//ˌædnˈɔɪdl//
adjective an adenoidal voice (= one that sounds as though you are talking through your nose, caused by adenoids swelling)See adenoids in the Oxford Advanced Learner's DictionaryCheck pronunciation: adenoids