What did expansionists mean by the term manifest destiny?

The doctrine of Manifest Destiny is a phrase and idea that expresses the belief that the United States of America is a nation destined to expand from the coasts of the Atlantic to the Pacific. This idea is also used by supporters to justify other territorial acquisitions. The supporters of this ideology believe that the expansion is not only good, but also obvious (manifest) and accurate.

i'd rather watch halloween but ok