Apostrophe

The apostrophe /əˈpɒstrəfiː/ is the symbol  &rsquo;  used extensively in English for contractions and for the possessive 's.

Use
The apostrophe is used to indicate:


 * possession, relationship, etc.: Susan’s book; today’s news; next week’s meeting;


 * omission of letters
 * Contractions: It’s mine; they’re here.
 * Normal omissions: o’clock (omitted "f"); ma’am (omitted "d"); goin’ (omitted "g", wich means /ɪn/ instead of /ɪŋ/).
 * Uncommon omissions: impo’tant is a spelling that emphasizes the lack of /r/ sound, i.e. /ɪmˈpɔːtənt/ rather than /ɪmˈpɔːrtənt/.


 * omission of numbers: May ’68;


 * it is sometimes used in plurals of abbreviations: CD’s (though most style guides recommend CDs);


 * in certain expressions of time: in two weeks’ time;

Greengrocer's apostrophe
A non-standard, but increasingly common use of the apostrophe is as a plural, as in potato's and tomato's.

Huntin’, shootin’ an’ fishin’
It is also quite common to hear words finishing in -ing (normal pronunciation /ɪŋ/) in which the final consonant is pronounced /n/. In spelling this is represented by substituting the final "g" by an apostrophe.

Examples include the upper class expression huntin’, shootin’ and fishin’, and the lyrics of pop and rock songs: cryin’ – drivin’ – dyin’ – livin’ – lyin’ – rockin’ – singin’ – sittin’ – talkin’ – walkin’ – etc.