Common English Abbreviations and Their Meanings

English abbreviations make messages shorter, label dates and measurements, and help readers recognize familiar organizations and concepts. But a shortened form that works in a text message may feel unclear or too casual in a report. Meaning also depends on context: Dr. commonly means “Doctor,” for example, but titles and conventions can vary by region and style guide.

This guide explains the difference between abbreviations, initialisms, and acronyms, clears up the often-confused e.g. and i.e., and gives 36 common forms in context. For more curated reference material, visit WordWise Hub’s abbreviations and reference pages.

Abbreviation, initialism, and acronym: what’s the difference?

An abbreviation is a shortened form of a word or phrase. Ave. for avenue and approx. for approximately are abbreviations. The term also covers forms built from initial letters.

An initialism is formed from the initial letters of a phrase and spoken as separate letter names: BBC (“B-B-C”) and ATM (“A-T-M”). An acronym, in the narrower sense, is formed from initial letters and pronounced as a word, as in NASA or NATO. Merriam-Webster notes that acronym is also commonly used more broadly for initial-letter forms such as FBI. In everyday writing, readers may encounter both usages, so use the more specific term when the pronunciation distinction matters. Merriam-Webster explains the distinction.

Some abbreviations are written with lowercase letters and periods; others use capitals without periods. That choice can depend on the abbreviation, the publication, and the style being followed. For example, U.S. and US both occur, though a particular style guide may prefer one form in a given context. APA recommends avoiding periods in most all-capital abbreviations, with exceptions such as U.S. before a noun; Chicago’s guidance keeps periods in e.g. and i.e. Purdue OWL summarizes APA conventions. When writing for a class, workplace, or publication, follow its style guide consistently.

36 common English abbreviations and meanings

Examples below are original illustrations of typical usage. Some entries are acronyms or initialisms as well as abbreviations; the category labels overlap.

Short form	Meaning	Context example
a.m.	Before noon; from ante meridiem	The call starts at 9 a.m.
p.m.	After noon; from post meridiem	The library closes at 6 p.m.
approx.	Approximately	The walk takes approx. 20 minutes.
ASAP	As soon as possible (initialism; often spoken as a word)	Please send the revised schedule ASAP.
Ave.	Avenue	The studio is on Pine Ave.
B.C. / BCE	Before Christ / Before the Common Era	The settlement dates to 300 BCE.
c. / ca.	Circa, meaning approximately, especially for dates	The portrait was made c. 1810.
CEO	Chief executive officer (initialism)	The CEO addressed staff at the meeting.
DIY	Do it yourself (initialism)	They used a DIY kit to build the shelf.
Dr.	Doctor; a title before a name	Dr. Lee will lead the seminar.
e.g.	For example; introduces examples	Bring a warm layer, e.g., a sweater.
etc.	And other things of the same kind	Pack a notebook, pens, sticky notes, etc.
ETA	Estimated time of arrival (initialism)	Her ETA is 4:30 p.m.
FBI	Federal Bureau of Investigation (initialism)	The report quoted an FBI spokesperson.
ft.	Foot or feet, a unit of length	The room is 12 ft. wide.
ID	Identification or identifying document	Show your ID at reception.
i.e.	That is; introduces a clarification or restatement	The meeting is remote, i.e., everyone joins online.
Inc.	Incorporated, used in some business names	North Star Design, Inc., opened a new office.
Jr.	Junior, often following a person's name	The invitation was addressed to Morgan Ellis Jr.
kg	Kilogram(s), a unit of mass	The parcel weighs 2 kg.
km	Kilometer(s), a unit of distance	The trailhead is 4 km away.
Ltd.	Limited, used in some company names	The invoice came from Greenfield Ltd.
max.	Maximum	Each group may include a max. of eight people.
min.	Minute(s), or minimum depending on context	Allow 15 min. for the exercise.
Mr.	Mister, a title	Mr. Patel will introduce the speaker.
Mrs.	A title traditionally used for a married woman	Mrs. Chen requested a printed copy.
Ms.	A title for a woman that does not specify marital status	Ms. Rivera is the new editor.
NASA	National Aeronautics and Space Administration (acronym)	NASA shared images from the mission.
No.	Number	Please take ticket No. 18.
Ph.D.	Doctor of Philosophy, an academic degree	He earned a Ph.D. in linguistics.
PO Box	Post office box	Send the form to PO Box 208.
RSVP	Please respond; from the French répondez s’il vous plaît	The invitation asks guests to RSVP by Friday.
St.	Street or Saint, depending on context	The shop is at 8 King St.; St. Anne’s is nearby.
U.S. / US	United States	She moved to the US last year.
vs.	Versus; against or in comparison with	The article compares print vs. digital dictionaries.
YTD	Year to date (initialism)	The team’s YTD spending is within budget.

In the table, B.C. and BCE express the same broad calendar designation in different conventions; BCE avoids explicitly Christian wording. St. can mean Street or Saint, so nearby words and formatting help readers identify which is intended. min. can likewise mean minute or minimum. Spell it out if the context does not make the intended meaning clear.

E.g. vs. i.e.: examples or explanation?

Use e.g. when you are giving one or more examples. The examples illustrate a broader group and do not necessarily list every possible item: “For the workshop, bring a writing tool, e.g., a pencil.”

Use i.e. when you are clarifying or restating what came immediately before it: “The final session is asynchronous, i.e., you can complete it on your own time.” The clarification is intended to specify what asynchronous means here. The Chicago Manual of Style’s explainer makes this specific-versus-general distinction clear. Chicago Manual of Style, “I.e., E.g., Etc.”

A useful check: if for example fits, choose e.g.; if that is fits, choose i.e. Do not automatically add etc. after e.g.: “e.g.” already signals that the list is illustrative, so the extra marker is usually redundant. Chicago’s style uses periods and generally places a comma after these forms, but punctuation preferences vary. In formal prose, some editors prefer spelling out for example and that is, especially outside parentheses, notes, or tables. Purdue OWL’s APA guidance also demonstrates that abbreviation rules belong to a defined style rather than to one universal punctuation system.

Make abbreviations easy to understand

Use an abbreviation when it genuinely helps readers, not just because it saves a few characters. For an unfamiliar or specialized term, write it out at first mention and put the shortened form in parentheses if you will use it again: “The community health centre (CHC) opens at eight.” In a short note, defining a rare abbreviation may create more clutter than writing the term in full. APA similarly advises limiting abbreviations to forms that are standard and clear, and recommends defining many nonstandard forms at first use. Purdue OWL: APA Abbreviations

Think about audience as well as style. ASAP is ordinary in many workplace messages, but “as soon as possible” may sound more considerate when a request needs a clear deadline. Spell out an unfamiliar acronym in public-facing writing, and avoid assuming that a technical abbreviation will be familiar to every reader. For more support, explore WordWise Hub’s guides to grammar, writing, and the basic grammar checker.

Consistency matters, but clarity comes first: define what readers may not know, choose a recognized form, and follow the relevant publication’s rules for capitalization, periods, and spacing.