Douglas Harper's Etymology Dictionary
Wiktionary
n. A very large city; a megalopolis.
Wikipedia
A megacity is usually defined as a metropolitan area with a total population in excess of ten million people. A megacity can be a single metropolitan area or two or more metropolitan areas that converge. The terms conurbation, metropolis and metroplex are also applied to the latter.
As of 2015, there are 35 megacities in existence. The largest of these are the metropolitan areas of Tokyo and Shanghai, each of these having a population of over 30 million inhabitants, with 38.8 million and 35.5 million respectively. Tokyo is the world's largest metropolitan area, while Shanghai has the world's largest city proper population.
Megacity is an iOS video game developed by ColePowered and released on August 2, 2011.
Usage examples of "megacity".
From up here on the ridge, two thousand feet above Santa Clara Valley, spread a view of the umbilical lines of light connecting sixty miles of solid megacity that stretched all the way from San Francisco to San Jose.
None of the Barrens that hedged in any of the megacity sprawls were kind or gentle places after dark.
Somehow they seemed to symbolize this new megacity, already the seventh largest in the country and almost twice the size of San Francisco.
There was no visible end to it, no glimpse of the megacity that he knew lay beyond.
The ground around them was a flat bed of asphalt squares, where nothing grew and nothing moved, a mile-wide security moat separating them from the megacity that they helped to energize.
It could see down onto the megacity that was two-thirds industrial facilities.
It was silent in the Chunatas, the noise of the megacity deflected by the foothills, a condition matching the land behind Randtown.
Beyond the highway, the megacity rolled away into the smoggy horizon, vast housing estates alternating with industrial precincts, stitched together by the curving lines of the railway tracks and highways.
This whole boiling megacity, this whole fun future world loves its gods.
We went from small villages where everybody knew each other to megacities in a matter of a few centuriesbefore we had the ability to evolve emotionally tougher hides.
Experts predict the rise of tens and perhaps hundreds of tropical megacities attracting vast new slum populations of lowest-paid labor, and producing unprecedented rates of killer diseases such as tuberculosis .
After it escaped from the processing plants, it spread through all the megacities and we've had to abandon huge areas to it.
To the scouting party it was only minutes since they'd entered the wormhole, but as soon as they came out they found a sterile planet, with the ruins of the megacities crumbling into dust.
We went from small villages where everybody knew each other to megacities in a matter of a few centuries—before we had the ability to evolve emotionally tougher hides.