Today’s topic is the difference between abbreviations, acronyms, and initialisms.

Abbreviations and acronyms

Any shortened form of a word is an abbreviation, for example, “etc.” for “etcetera” and “Oct.” for “October”; but acronyms are a special kind of abbreviation, such as “ROFL” (rolling on the floor laughing) and “OPEC” (Organization of Petroleum Exporting Countries), that can be pronounced as words. This makes them a subset of abbreviations. All acronyms are abbreviations, but not all abbreviations are acronyms.

Initialisms

Initialisms are another type of abbreviation. They are often confused with acronyms because they are made up of letters, so they look similar, but they can’t be pronounced as words. “FBI” and “CIA” are examples of initialisms because they’re made up of the first letters of “Federal Bureau of Investigation” and “Central Intelligence Agency,” respectively, but they can’t be pronounced as words. NASA, on the other hand, is an acronym because even though it is also made up of the first letters of the department name (National Aeronautics and Space Administration), it is pronounced as a word, “NASA,” and not by spelling out the letters “N, A, S, A.”

So remember:

• Initialisms are made from the first letter (or letters) of a string of words, but can’t be pronounced as words themselves. Examples include “FBI,” “CIA,” “FYI” (for your information), and “PR” (public relations).
• Acronyms are made from the first letter (or letters) of a string of words but are pronounced as if they were words themselves. Examples include “NASA,” “NIMBY” (not in my backyard), and “hazmat”* (hazardous materials).
• Abbreviations are any shortened form of a word.

Style guide

Finally, there’s no strict rule about putting periods after each letter in an acronym or initialism. Some publications put periods after each letter, arguing that because each letter is essentially an abbreviation for a word, periods are necessary. Other publications don’t put periods after each letter, arguing that the copy looks cleaner without them, and that because they are made up of all capital letters, the fact that they are abbreviations is implied.

Links

• Wikipedia Entry for Acronyms and Initialisms
  Dictionary.com entry for Initialism
  An excellent discussion by HTML developers about acronyms and abbreviations.
  List of Common Abbreviations
• * I haven’t been able to find a definitive answer on the right way to write “hazmat,” but the U.S. government’s Office of Hazardous Materials Safety writes it as “hazmat” so I’m sticking with that for now.
• Image courtesy of Shutterstock.