What is sexual harassment and sexual assault?

"Is kissing someone when they don't want it ass*ult?"
What's the difference between s*xual harassment and s*xual assault?
Is it s*xual harassment to touch someone in a non-s*xual way without their permission?

When we know the answers to these questions, we're better at keeping people safe, understanding the harm caused by s*xual assault, and supporting friends who may have been affected.