ABBREVIATIONS

How are periods handled when abbreviating?

In general, eliminate periods unless the abbreviation spells a normal word:

AMA		DOE		OPEC		YWCA

in. = inches (not in)		no. = number (not no)

Units of measure that are abbreviated do not have periods, and the same abbreviation is used for both the singular and plural:

cm		ft		lb		m

mm		oz		yd		yr

Some abbreviations still require periods:

a.d.	a.m.	b.c.	Dr.	e.g.	etc.

i.e.	Mr.	Mrs.	Ms.	p.m. 	pp.

When using periods in abbreviations, do not put a space between the period and the next letter:

a.d. (not a. d.)	i.e. (not i. e.)

When an abbreviation ends a sentence, use only a single period:

The meeting will begin at 10:00 a.m.

If the sentence or clause ends with punctuation other than a period, the other mark of punctuation follows the period of the abbreviation:

Will the session be over by 4:30 p.m.?

After 7 p.m., the hotel restaurant is often filled to capacity.

May a word be abbreviated that is connected to another word by a hyphen?

No. Spell out abbreviated words that are connected to other words by hyphen.

10-foot pole (not 10-ft pole)	6-inch pipe ( not 6-in. pipe)

When may a unit of measurement, such as in. or ft, be abbreviated?

Do not abbreviate a unit of measurement unless it is used in conjunction with a number:

The measurements in the schematic diagram are given in 

meters and feet. (not m and ft)

but 

The building that we're planning to use for storing supplies is 

24 ft by 40 ft. 

The diameter of the opening is 3 cm.

When is it permissible to use the symbol forms of abbreviations?

Avoid using symbol forms of abbreviations except in graphs, charts, illustrations, and other visual aids:

36.38 IN. (not 36.38")		22 PCT (not 22%)

May an abbreviation be used at the beginning of a sentence?

The preference is to spell out abbreviations that begin a sentence (except for abbreviated words that are never spelled out, like Mr. and Mrs.):

Electromotive force causes a greater quantity of electricity 

to flow through an electric circuit. 

not 

Emf causes a greater quantity of electricity to flow through an 

electric circuit. 

but 

Mr. Alfonso Guiterrez will assume the position of chief 

comptroller on Wednesday.

Is it permissible to abbreviate the names of months and days in normal text?

Generally, avoid abbreviating the names of months and days in normal text. Reserve the use of these abbreviations for tables, charts, chronologies, and other visual representations:

Our Quality Improvement Program will officially commence 

in September 1996. (not Sep 1996 or 9/96)

How are acronyms appropriately handled?

An unfamiliar acronym or abbreviation that will appear numerous times in a document should be clarified by enclosing its unabbreviated form within parentheses after its first use:

The aims of the WRC (Women's Relief Corps) were to aid and

memorialize the GAR (Grand Army of the Republic). 

One liter contains one dm3 (cubic decimeter) of water and 

weighs one kg (kilogram).

Placing the unabbreviated form first (and the acronym in parentheses) is not incorrect, but it may inhibit reader comprehension since the acronym will not be enclosed in parentheses in the remainder of the document.

Obviously, it is useless to introduce an acronym with its unabbreviated form if it will only be used once in the same document.