A mutex (short for "mutual exclusion") is a programming construct used to manage access to shared resources in a concurrent environment. It ensures that only one thread or process can access a resource at a time, preventing conflicts and data corruption. When a thread wants to use a resource, it must first "lock" the mutex. If another thread tries to lock the same mutex, it will be blocked until the first thread releases it. Mutexes are essential in multi-threaded applications, where multiple threads may attempt to read or write to the same data simultaneously. By using a mutex, developers can synchronize access to shared resources, ensuring that operations are performed safely and consistently. This helps maintain the integrity of the data and improves the overall stability of the application.