ablarc: I just saw your STREETWALLS OF PARIS post -- incredible! Thanks ...
A couple of weeks back I was going to argue that the Flatiron, while an iconographic NYC building, didn't necessarily fit into the "skyscraper" category.
Then I did some research and realized how little I know about what I think I know
As I'm sure you're aware: at 285' the Flatiron was not the tallest building in NYC when it was built in 1902 -- it was preceded by the 309' New York World Building (1890 - demolished 1955), the 348' Manhattan Life Insurance Building (1894 - demolished 1930 [ ??? ]) and the 391' Park Row Building (1899 - still standing across Park Row from City Hall Park).
The word SKYSCRAPER apparently was first used in conjunction with a type of building in 1883 (before any of the above-mentioned buildings were constructed):
As seen in this drawing the Flatiron certainly fit the bill of a "skyscraper" in its early days:
Before it became a building, Americans knew skyscraper
as "a high-flying bird" (1840), "a tall hat or bonnet" (1847), or "a high fly ball in baseball" (1866). But in 1883, a visionary writer in American Architect and Building News
"a public building should always have something towering up above all in its neighborhood.... This form of sky-scraper gives that peculiar refined, independent, self-contained, daring, bold, heaven-reaching, erratic, piratic, Quixotic, American thought ('young America with his lack of veneration'). The capitol building should always have a dome. I should raise thereon a gigantic 'sky-scraper,' contrary to all precedent in practice, and I should trust to American constructive and engineering skill to build it strong enough for any gale."
The West End Ave / Park Avenue streetwall buildings, by the very nature that they are a collection of buildings in a row, seems to preclude them from being described as skyscrapers -- even if their individual height puts them in the company of other earlier individual skyscrapers.
In my eye a building has to have some individual relationship to the sky to earn the tag "skyscraper". This causes trouble for all the 50-story buildings clumped together in business districts -- and leads to the unpopular "plateau" effect that is so often bemoaned here and elsewhere.