When components are strongly tied to each other, meaning the failure of one component would force whatever operation was going on to be restarted, we say they’re “tightly coupled.”
Consider a web application that processes customer orders. One potential point of vulnerability in the order processing workflow is in saving the order in the database. As a new requirement, the business expects that every order has been persisted into the database. However, any potential deadlock, race condition, or network issue could cause the persistence of the order to fail. Then, the order is lost with no recourse to restore the order.
This concept will link to Decoupling concept.