>[!abstract] >The mean sojourn time (or sometimes mean waiting time) for an object in a dynamical system is the amount of time an object is expected to spend in a system before leaving the system permanently. This concept is widely used in various fields, including physics, chemistry, and stochastic processes, to study the behavior of systems over time (Wikipedia, 2025). >[!related] >- **North** (upstream): [[Markov processes]] >- **West** (similar): [[Mean first passage time]] >- **East** (different): [[Instantaneous transition]] (zero sojourn time) >- **South** (downstream): [[Residence time distribution]]