Acronym vs abbreviation comes down to one idea: abbreviation is the big category for any shortened word or phrase, and an acronym is one type inside it, built from first letters and spoken as a word. So Mr., tsp. and Jan. are abbreviations, while NASA and SCUBA are acronyms, and acronyms are abbreviations too.
A third term sits between them. An initialism is also made from first letters, but you say each letter on its own, as in CPR or USB. Once you know the three labels, you can sort almost any short form by asking two questions: is it made from first letters, and do you say it as a word?
Quick facts
Abbreviation
Any shortened form of a word or phraseAcronym
Initials said as one word, like NASAInitialism
Initials said letter by letter, like CPRRelationship
Acronyms and initialisms are both kinds of abbreviationQuick test
Can you say it like a word? Then it is an acronymDifference between acronym and abbreviation
Scope: abbreviation is the whole group, acronym is one memberRelated terms
Backronym, acrostic, clipping
Acronym vs abbreviation vs initialism at a glance
| Type | How it is made | How it is said | Examples |
|---|---|---|---|
| Abbreviation | Any part of a word or phrase is cut | Usually the full word | Dr., Ave., approx., Feb. |
| Initialism | First letters of several words | Letter by letter | CPR, USB, CEO |
| Acronym | First letters (or parts) of several words | As a single word | OSHA, FEMA, PIN |
Think of it as a family tree. Abbreviation is the parent. Acronym and initialism are two children who look alike on paper and sound different out loud. The acronym side of the family gets a longer look in our acronym basics guide.
What is an abbreviation?
An abbreviation is any shortened form of a word or phrase that stands in for the whole thing. The cut can happen in several ways, and most of them have nothing to do with first letters.
- Cutting the end: Feb. for February, approx. for approximately.
- Keeping the first and last letters: Dr. for doctor, Mr. for mister, St. for street.
- Using a standard symbol or code: lb for pound, oz for ounce, tsp for teaspoon.
- Clipping: a short piece that became a word of its own, such as lab for laboratory or exam for examination.
When you read most abbreviations aloud, you say the full word. Nobody reads "Ave." as "av." Word pages like the abbreviation for teaspoon and month abbreviations show how these are written.
What is an initialism? Examples you see every day
An initialism is a short form pieced together from the opening letters of a phrase, then spoken one letter after another. Plenty of people call these acronyms in casual talk, and that is common enough that few readers will object. Style guides, teachers and editors, though, keep the two apart.
| Initialism | Full form |
|---|---|
| HR | Human resources |
| IRS | Internal Revenue Service |
| GPS | Global Positioning System |
| PTO | Paid time off |
| DIY | Do it yourself |
| TBD | To be determined |
These initialism examples share one trait: try to say them as words and they fall apart. "Irs" and "gups" are not sounds English speakers make, so we spell them out.
Acronym vs initialism: the say it out loud test
Here is the fastest way to decide acronym or initialism. Read the letters aloud the way people really say them.
- If you blend the letters into one word, it is an acronym. HIPAA becomes "HIP uh." PIN rhymes with win.
- If you name each letter, it is an initialism. ATV is "A T V." FAQ is often "F A Q."
- If people do both, it counts as either one, depending on the speaker.
In an office: one coworker asks about the "F A Q" page while another calls it the "fack" page. Both are right. FAQ works as an initialism for the first person and an acronym for the second.
Some short forms mix the two styles. JPEG is said "JAY peg," with the J named as a letter and the rest said as a word. CD-ROM is an initialism joined to an acronym. These hybrids are rare, so the two-way test handles almost everything.
Abbreviation vs acronym examples side by side
| Short form | Full form | Type | Why |
|---|---|---|---|
| Mon. | Monday | Abbreviation | The end of the word is cut |
| Blvd. | Boulevard | Abbreviation | Key letters kept from one word |
| YMCA | Young Men's Christian Association | Initialism | Said letter by letter |
| UFO | Unidentified flying object | Both | Said "U F O" or "YOO foe" |
| Scuba | Self-contained underwater breathing apparatus | Acronym | Said as a word, now often lowercase |
| ZIP code | Zone Improvement Plan code | Acronym | Said as the word zip |
The scuba and ZIP rows show a quiet change that happens over time. Some acronyms get used so often that people forget the letters stood for anything. A few writers call these anacronyms, a playful term for an acronym whose full form most people no longer know.
Initials, acrostics and other look-alikes
- Initials vs acronym: a person's initials, such as the letters on a monogrammed towel, are a kind of initialism. They become an acronym only if people say them as a word.
- Acronym vs acrostic: an acrostic is a poem or puzzle where the first letters of each line spell a word down the side. An acronym is a single word made from initials. Many memory tricks are acrostics, a sentence where each word's first letter cues something to remember. See the memory acronyms for both kinds.
- Backronym: a phrase made up after the fact to fit an existing word, often in a false origin story.
- Initialization vs acronym: initialization is a computer term for setting starting values. When people type it in a search about short forms, they almost always mean initialism.
How to write acronyms and initialisms
A few habits keep your writing clear, whatever the short form is called.
- On first mention, write the name in full and tuck the letters into parentheses behind it: "the Federal Emergency Management Agency (FEMA)."
- Choose a or an by sound, not spelling: "an HR form" (aitch), "a NASA mission" (nah).
- Make plurals with a plain s and no apostrophe: ATMs, CEOs, PINs.
- Most acronyms and initialisms skip periods in American English today: US and U.S. are both used, but style guides differ.
- Do not repeat a word the letters already include, such as "PIN number," unless the redundant form is so common it reads more naturally to your audience.
Regular shortened words have their own habits for dots and capital letters, explained in how to abbreviate.
Questions people ask
How do acronyms differ from abbreviations?
An abbreviation is any shortened form of a word or phrase. An acronym is one narrow kind of abbreviation, built from initials and pronounced like a regular word, such as NASA.
Is every acronym an abbreviation?
Yes. Acronyms and initialisms are both types of abbreviation. The reverse is not true: Dr. and Feb. are abbreviations but not acronyms.
What is an initialism?
It is a set of initials you read aloud letter by letter, such as IRS or DIY. Many people loosely call these acronyms.
Is FBI an acronym or an initialism?
By the strict definition FBI is an initialism, since every letter gets named aloud. Casual speakers often label it an acronym anyway, and nobody is confused.
How is an acronym different from an acrostic?
An acronym is a word built from initials. An acrostic is a poem, puzzle or sentence where the first letters of lines or words spell out something.
Can an abbreviation be both an acronym and an initialism?
Yes, when people say it both ways. UFO and FAQ are common examples of short forms said either as letters or as a word.