The apostrophe (2)

We saw in the last article that one of the apostrophe's main functions is to denote possession. Today we are going to look at its other uses.

The apostrophe's other main use is to replace letters omitted from a word that has been shortened or contracted. An example is my own surname, O'Donnell, which originally meant son of Donnell, but an apostrophe now replaces the letter f. Similarly, as we know from our last article, it's is not a possessive form, rather the apostrophe replaces the letter i to form the contracted form of it is.

The apostrophe's use in contractions falls into one of several categories:

Never forget that although contractions are widespread in spoken English and even make the speaker sound much more natural, they should always be avoided in formal writing - only in informal correspondence are they really acceptable.

The apostrophe can also be used to denote plurals where the written form could prove confusing otherwise, in particular for numbers and very short abbreviations.
Examples: Our sales prices in the 1980's were higher than they are now.
My name is spelt with two i's.
He regaled me with if's and but's.
The apostrophe must not be used to form plurals in any other circumstances.