Contractions in English are the shortening of words, phrases, or numerals by omitting characters and replacing them with an apostrophe. The apostrophe represents the missing letters or numbers. You likely use contractions daily in your communications.

Certain words are sometimes written with an apostrophe (to show that they are really a shortened form of the original, longer word): influenza → 'flu (or flu) telephone → 'phone (or phone)

We use apostrophes with some shortened forms of words (which we call contractions). We use full stops or no punctuation with other shortened words (which we call abbreviations). The one clear difference between contractions and abbreviations is the punctuation used.

Use an apostrophe when you’re shortening or combining words. you are becomes you’re do not becomes don’t it is or it has becomes it’s (Note that this is one of the most common mistakes of the amateur writer.