A contraction is a shortened form of one or two words created by removing some letters and replacing them with an apostrophe. When you write don't instead of do not, or I'm instead of I am, you're using contractions. They make writing sound more like natural speech.

Contractions appear everywhere in everyday English. You might say can't for cannot, we'll for we will, or they're for they are. Some contractions combine a pronoun and a verb (she's, he'd, you've), while others combine a verb and the word not (isn't, won't, shouldn't). Notice that won't looks nothing like will not: it's one of English's quirky exceptions.

People often confuse contractions with possessives because both use apostrophes. Remember: it's means it is (a contraction), while its shows possession (like its tail). Similarly, they're means they are, while their shows possession (like their backpacks), and there indicates a place.

In a different scientific sense, contraction means the process of something becoming smaller or tighter. When you're cold, your muscles experience involuntary contractions (they tighten up), which causes shivering. Metal contracts when it cools and expands when it heats up, which is why bridges have special joints to allow for expansion and contraction.