1. To lean someone or something against someone or something else. I propped him up against the side of the building until our taxi arrived. Just prop the rake against the shed when you're done.

2. To help someone or something remain upright with a prop or crutch of some kind. The frame of my bed broke right in the center, so I've been propping it up with a stack of books. I propped up the picture frame with a piece of cardboard to keep it from tipping over.

3. To give someone or something support in order to remain active or keep from failing, especially in a temporary, partial, or secretive capacity. The American film industry props up the entire country's economy—if they decided to go elsewhere to film, hundreds of thousands of people will lose their jobs overnight. My father propped my business up for the first few years to help keep me afloat. It's only just now that I can begin paying him back. Of course it's now known that the United States had been propping dictatorships and shadow presidents up all around the world in order to protect American interests.