1 definition by ProudUSian

A demonym, used especially in internet based writing, used to indicate that someone or something is of the United States of America. This is contrasted with "American," which technically means someone or something belonging to North or South America, including such disparate places as Guyana, Mexico, and Canada.
Damaris, Ashley, and Yulisa are all Americans, but only Damaris is USian.
by ProudUSian March 15, 2011
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