Apostrophes to show plurals of abbreviations.

An apostrophe can be used to show the plural of an abbreviation. (Read this section carefully.)

1. The plurals of abbreviations, letters and numbers can be written using apostrophes. For example:

He sent 3 SOS's between midnight and 6 a.m.

There are two a's in accommodation.

Your 2's look like your 7's.

1000's of bargains.

2. The advantage of using an apostrophe is that the abbreviation or letter is instantly recognisable. However, apostrophes can also be used for possession. Therefore, when apostrophes are used to show plurals, it can lead to ambiguity.

Example:

MP's plan failure
(Is this about:

- ministers planning to fail, or
- the failure of a minister's plan?)

3. Do not use apostrophes for the plurals of normal abbreviations.

Examples:
M.O.T.'s (M.O.T.s )
(MOT - Ministry of Transport / also "Ministry of Transport test")

MOT's (MOTs )

Note: It is often the writer's choice whether to use full stops in abbreviations.
(See lesson "Abbreviations".)

He had 4 CCJ's against him. ( He had 4 CCJs against him. )
(CCJ - County Court Judgment)

AVOID USING AN APOSTROPHE

Some grammar books (not all) claim that apostrophes cannot be used in any plurals. This is considered an outdated view by many. In the 4 examples to the left, the apostrophes assist the reader and are acceptable. However, the plural of a normal-looking abbreviation should be shown by adding a small "s" without an apostrophe.

Associated lessons:

The apostrophe error with plurals
Apostrophes in time (temporal) expressions
Apostrophes replace letters
Apostrophes show possession