Abbreviations/Acronyms Abbreviations and acronyms are used to save space and to avoid distracting the reader. Acronyms that abbreviate three or more words are usually written without periods (exception is U.S.S.R.). Abbreviations should only be used if the organization or term appears two or more times in the text.
What is the rule for using acronyms?
Introducing acronyms
The first time you use the term, put the acronym in parentheses after the full term. Thereafter, you can stick to using the acronym. Note that when introducing an acronym, the full term should only be capitalized if it is a proper noun (e.g. the name of an organization).
Is it okay to use acronyms?
Abbreviations and acronyms are shortened forms of words or phrases. Generally, abbreviations are not acceptable in academic writing (with some exceptions, see below) and acronyms are (providing they are used as shown below).
Where does the acronym best apply?
The word acronym typically applies when the resulting thing can be read as a word; for example, radar comes from "radio detection and ranging" and scuba comes from "self-contained underwater breathing apparatus." The word initialism only applies when the resulting thing is read as an abbreviation; for example DIY, ...