Wordnet 3.0
NOUN (1)
1.
a very large urban complex (usually involving several cities and towns);
The Collaborative International Dictionary of English v.0.48:
Megalopolis \Meg`a*lop"o*lis\, Megapolis
\Meg`a"po*lis\(m[e^]g`[.a]*l[o^]p"[-o]*l[i^]s), n. [NL., fr. Gr.
megalo`polis; me`gas, mega`lh, great + po`lis city.]
1. A chief city; a very large cuity; a metropolis.
[1913 Webster]
2. A region in which the suburbs of several large cities
merge to form one large predominantly urbanized area.
[PJC]
WordNet (r) 3.0 (2006):
megalopolis
n 1: a very large urban complex (usually involving several
cities and towns)