arteriosclerosis Syllabification: (ar·te·ri·o·scle·ro·sis)Pronunciation: /ärˌti(ə)rēōskləˈrōsis/Definition of arteriosclerosis noun Medicine the thickening and hardening of the walls of the arteries, occurring typically in old age. Derivatives arterioscleroticPronunciation: /-ˈrätik/ adjective arteriosclerosis in other Oxford dictionaries Definition of arteriosclerosis in the British & World English dictionary