megacity

The term 'megacity' is a modern compound, formed in the late 20th century to describe the phenomenon of explosively growing urban centers. Its first element, 'mega-', is borrowed directly from the Greek adjective megas, meaning 'great' or 'large', which has been productively used in scientific and technical vocabulary (e.g., megawatt, megabyte) to indicate an extreme magnitude. The second element, 'city', traces back to the Latin civitas, a term encompassing the body of citizens, their community, and the physical city itself. The compound's logic is transparently literal: a 'megacity' is simply a 'very large city', directly linking the ancient Greek concept of greatness to the contemporary urban reality defined by a specific, massive population threshold.

Structure: mega (large) + city (city) - mega: From Greek megas (great, large). A combining form used in English to denote something of great size or scale. - city: From Old French cite, from Latin civitas (citizenship, state, city), from civis (citizen). The base word for a large and permanent human settlement.