apse Syllabification: (apse)Pronunciation: /aps/Translate apse | into Italian Definition of apse noun 1a large semicircular or polygonal recess in a church, arched or with a domed roof, typically at the eastern end, and usually containing the altar. 2another term for apsis.Derivatives apsidalPronunciation: /ˈapsidl/ adjective Origin: early 19th century (sense 2): from Latin apsis (see apsis)apse in other Oxford dictionaries Definition of apse in the British & World English dictionary