What's is a contraction, which means it's two words squeezed together into one. It combines “what” and “is” (or sometimes “what” and “has”). That little apostrophe shows where letters got left out.

You use what's constantly in everyday speech. What's your name? What's for dinner? What's going on? Each time, you're really saying “what is.” The contraction makes speech flow more naturally than saying both words separately.

Sometimes what's means “what has,” though this is less common. You might say “What's happened here?” meaning “What has happened here?” You can usually tell which meaning fits from context.

Contractions like what's appear everywhere in casual writing: texts, emails, dialogue in stories. However, in formal essays or reports, many teachers prefer you write out “what is” instead. Knowing when to use contractions and when to avoid them is part of learning to match your writing style to your audience.

The word creates questions that help you learn and understand: What's the answer? What's the difference between these two things? What's the big idea? These questions drive curiosity forward.