To get something across means to successfully communicate an idea so that others understand it. When a teacher gets a difficult math concept across to her students, she's explained it clearly enough that they finally grasp what she means. When you're trying to get your point across in an argument with your brother, you want him to truly understand your perspective, to see why you think the way you do.

The challenge goes beyond speaking or writing: you have to present your thoughts in a way that makes sense to your specific audience. A scientist might struggle to get her research across to people outside her field because she's using too much technical language. A student giving a presentation needs to get the main ideas across without boring the class with unnecessary details.

Sometimes getting something across requires creativity. You might use examples, draw diagrams, tell stories, or try different words until that “aha!” moment when the other person finally gets it. If you're having trouble getting an idea across, it helps to think about what the other person already knows and build from there. The phrase suggests a journey: your thought needs to travel from your mind, across the space between you, and land clearly in someone else's understanding.