Mutex
/ˈmjuː.tɛks/ · Noun · Development · Origin: 1965
Definitions
Mutual Exclusion — a synchronization primitive that ensures only one thread can access a shared resource at a time, preventing race conditions. The programmatic equivalent of a bathroom door lock.
In plain English: A lock that ensures only one part of a program can use a shared resource at a time — like a key to a single-occupancy bathroom.