Sentence:  It is an understandable paradox that most American history and most American literature is today written from an essentially egocentric and isolationistic point of view at the very time <WSD>America</WSD> is spreading her dominion over palm and pine . 
Meaning of the word marked with <WSD> tags:  North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776