from
The Collaborative International Dictionary of English v.0.48
Hyphenated American \Hyphenated American\
An American who is referred to by a hyphenated term with the
first word indicating an origin in a foreign country, and the
second term being "American", as {Irish-American},
{Italian-American}, {African-American}, {Asian-American}.
Used in reference to Americans of foreign birth or ancestry.
When used of Americans of European ancestry, it is often used
to refer to those who have a strong attachment to the
ancestral country or its culture. It implies that the
individual is imperfectly assimilated into American culture,
and is sometimes used derogatively.
[Webster 1913 Suppl.]