吴哥 = 'Angkor' (transliteration); 城 = 'walled city.' Angkor Thom literally means 'great city' in Khmer. Chinese chose 城 because the site's defining feature is its 12-km moated city wall, distinguishing it from the temple-only 吴哥窟.
吴哥城 (Angkor Thom, the 'great city' built by Jayavarman VII around 1200) is distinct from 吴哥窟 (Angkor Wat, the temple complex of Suryavarman II). Both are part of the Angkor Archaeological Park, a UNESCO World Heritage site.
