Abbreviations: Initialisms, Acronyms, and Backronyms; What is the Difference?

A lot of people today use the words acronym and initialism interchangeably, but there are actually a few things to keep in mind when understanding the differences between these terms.

What is an Abbreviation?

What does abbreviation mean? To starts, let’s look at the term abbreviation. An abbreviation is a shortened form of a word or phrase used to represent the whole. An example of an abbreviation would be Nov. used to represent November or etc. for the word etcetera. Abbreviations are not the same as acronyms. Acronyms are, however, a subset of abbreviations. Initialisms and backronyms are also subsets of abbreviations.

What is an Acronym?

acronym-vs-initialismWhat does acronym mean? An acronym is a word that is formed from the first letter (or letters) of a series of words. A classic example of an acronym is NATO, from the North Atlantic Treaty Organization. Another example is radar from (ra)dio (d)etecting (a)nd (r)anging. The key feature with an acronym is that the word that is formed from the initial letters is pronounced as if it were a word. This is what differentiates acronyms from initialisms.

What is an Initialism?

What does initialism mean? An initialism is an abbreviation consisting of the first letter (or letters) of words in a phrase, syllables or components of a word, or combination of words and syllables. For example, FBI comes from the first letters of the phrase Federal Bureau of Investigation. TNT comes from the syllables in trinitrotoluene. The difference between initialisms and acronyms is that initialisms are pronounced by spelling out the letters one by one rather than as a solid word.

What is a Backronym?

What does backronym mean? Most people are unaware that this word even exists. A backronym is an acronym coined from an existing word or phrase. For instance, many governmental laws consist of backronyms. The USA PATRIOT Act is a backronym, standing for Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001.


In short, acronyms, initialisms, and backronyms are all forms of abbreviations.

  • Acronyms are pronounced as if they were words like NATO and radar.
  • Initialisms are pronounced by saying each individual letter one by one like FBI and TNT.
  • Backronyms are simply acronyms after the fact, an existing word for which someone creates an acronym.

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