Madison Avenue 1 a street in New York City, regarded as the center of the U.S. advertising industry 2 this industry, its practices, its influence, etc. (Webster's New World College Dictionary)Here's a better one:
Madison Avenue
noun
U.S. advertising industry: the center of the U.S. advertising and public-relations industries, or the U.S. advertising industry itself
[Named for the street in New York that is the center of the advertising industry] (Encarta World English Dictionary, online edition)
Madison Avenue, n. 1. an avenue in New York City, once the principal location for advertising firms. 2. the U.S. advertising industry. (Random House Webster's College Dictionary)In contrast, Yoshiwara in Tokyo is still a major red light district, but many dictionaries refer to it in the past tense:
よしわら 【《吉原】東京の台東区にあった遊郭。なか。（新明解国語辞典）
よしわら《吉原》江戸時代の遊郭。現在の東京都台東区浅草にあった。（新選国語辞典）
(January 9, 2003)