What does 'time to propagate' mean in a peer-to-peer network?

Time to propagate is how long it takes for data to spread from one computer to all the others across a peer-to-peer network. In a peer-to-peer network, nodes share information directly with each other — there is no central computer overseeing or routing the process. This means new data must travel organically from node to node until every participant has received it, rather than being pushed out instantly from a single server. Understanding propagation time helps beginners see why decentralized networks behave differently from apps run by a central server: the network's awareness of the latest state spreads gradually, not instantly.