Abbreviations

Abbreviations & Acronyms is an offline guide to over 1,000 English abbreviations, acronyms and initialisms, each with its full form and a short note on meaning and usage.

Look up what an abbreviation stands for, from a.m. and ASAP to UTC and WHO, and learn how to write it correctly in American and British English.

Every entry gives the abbreviation, its full form and, where it helps, a usage note. Long lists have a filter box, and you can search the whole app from the home screen, so you can find any full form in seconds.

What you will find

• How Abbreviations Work: abbreviations, acronyms and initialisms explained; periods in US and UK style (Mr. or Mr, U.S. or US, Ph.D. or PhD); plurals, possessives and "a" or "an"; spelling out and capital letters

• People, Titles and Ranks: personal titles and honorifics (Mr, Mrs, Ms, Mx, Dr); academic degrees; professional letters and British honours; US Army, Marine Corps, Navy and Air Force ranks; British Army, Royal Navy and Royal Air Force ranks; police ranks

• Places and Addresses: all 50 USPS state codes plus DC, the territories and military mail; the 13 Canadian province and territory codes; 66 ISO 3166 country codes; street, address and map abbreviations

• Dates and Time: days, months and date formats, AD, BC, CE and BCE, a.m. and p.m., and 27 time zone entries (UTC, GMT, EST, PST, CET, IST, JST and more)

• Units and Symbols: why SI symbols are not abbreviations, the 7 SI base units and 22 derived units with special names, all 24 SI prefixes from quecto to quetta, and US customary units

• Latin Abbreviations: e.g. or i.e.?, etc., et al., cf., viz., N.B., P.S., and the Latin of references and law

• Business and Technology: Inc., Ltd, LLC and PLC; CEO, CFO and other job titles; ROI, KPI, EBITDA and 19 ISO 4217 currency codes; office and email acronyms such as ASAP, FYI, EOD and RSVP; computer, internet and file format abbreviations

• Science and Medicine: DNA, pH, UV and other science abbreviations, how to shorten scientific names (E. coli, sp., spp.), and common medical abbreviations

• Everyday and Online: common everyday abbreviations, 40 texting and chat acronyms (LOL, BRB, TBH, FOMO, TL;DR), and international organizations such as the UN, WHO, NATO and the EU

• Mistakes and Practice: the most common abbreviation mistakes, and 20 practice questions with answers

Features

• Over 1,000 English abbreviations and acronyms with their full forms

• Clear usage notes, with American and British conventions side by side

• Official codes from USPS, Canada Post and ISO, and unit rules from the SI Brochure

• Simple diagrams of the kinds of abbreviation, the 12-hour and 24-hour clock, and world time zones

• Filter boxes on long lists, plus search across the whole app

• Dark mode

• Works offline, no account needed

• Available in 8 languages: English, Español, Português, Français, Deutsch, العربية, हिन्दी and Bahasa Indonesia. The abbreviations and full forms stay in English; the explanations are translated

Who it is for

• Students and English learners who meet an unfamiliar abbreviation or acronym

• Writers, editors and office workers who want to use abbreviations correctly

• Anyone who reads English news, email or chat and wants to know what an abbreviation stands for

Abbreviations & Acronyms is an independent study aid. It is not affiliated with any style guide publisher, postal service, standards body or government.