The Grammatical Term “Abbreviation” is a term which refers to a shortened form of a word or (sometimes) phrase.
Wisconsin (the state I grew up in) is abbreviated as WI
Previously It was abbreviated as Wisc. then Wis. and now simply as WI – notice that the periods disappeared and the abbreviations actually got abbreviated. This is a convention of all the states in the United States.
The United States of America is abbreviated as USA or even more simply the US
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