Acronyms, Contractions, Initialisms, and Shortenings: What You Need to Know About Abbreviations

Abbreviations, an area of uncertainty for many people, not knowing where to:

• write abbreviations with capital letters
• write full stops
• to use apostrophes

There are different kinds of abbreviations, and the way the abbreviation is written relies on the category it belongs to.

Acronyms

Words that are formed from initial letters of other words and pronounced as they are spelled.  A few examples:

Aids
Acquired immune deficiency syndrome

NATO
North Atlantic Treaty Organisation

UNESCO
United Nations Educational, Scientific, and Cultural Organisation

SIM (Card)
Subscriber Identification Module

Note: Most acronyms can be written as capital letters or with an initial capital letter at the beginning of  the word.

Some are well-established within society, so much so,  that they've become 'normal' words.  More examples:

Laser
Light amplification by stimulated emission of radiation

Radar
Radio detection and ranging

Quango
Quasi-autonomous  non-governmental organisation

Scuba
Self-contained underwater breathing apparatus

Contractions

A contraction is an abbreviation with letters removed from the middle of the word.  A few examples:

• Dr - Doctor
• St - Saint
• Ltd - Limited
• Revd - Reverend

Contractions can also appears as abbreviated forms of more than word. 

For example:

• I'll - I will/I shall
• We've - We have
• Shouldn't - Should not

Initialisms

Initialisms are abbreviations consisting of initials (first letters) of words pronounced as separate letters when spoken.  For example:

• BBC - British Broadcasting Association
• MP - Member of Parliament
• UN - United Nations
• UK - United Kingdom
• CD - Compact Disc

Note: Full stops aren't required after the letters in an initialism.

Apostrophes aren't required when forming the plural of an initialism.  Examples:

CDs - I bought some CDs last week.
MPs - MPs took a vote against the bill last night.

Shortenings

A shortening is an abbreviation where the end or beginning of a word has been dropped.  For example:

• Cello - violincello
• Flu - Influenza
• Ad - Advertisement
• Blog - Weblog
• Telly - Television
• Bike - Bicycle