OSPF
In plain terms
A routing protocol that finds shortest paths within a network.
Going deeper
Open Shortest Path First lets routers within an organization share link states and compute optimal routes using Dijkstra's algorithm. It's an interior gateway protocol.
Under the hood
Link-state and fast-converging; used inside autonomous systems, unlike BGP which routes between them.
Examples
Enterprise routing, internal networks, link-state routing, data centers.
Think of it like...
Like every intersection sharing traffic maps so each finds the fastest internal route.