thread

The term thread derives from Old English thræd meaning a cord or string. It originally referred to a long slender strand of material used for sewing or weaving. In modern usage the word also denotes a conceptual line of execution in computing, linking the textile and software senses by analogy.

In textiles, a thread is a flexible strand produced by twisting together fibers such as cotton, silk, or synthetic filaments. Threads are wound on spools or cones and used for sewing, embroidery, and weaving. Common variations differ in fiber, diameter, twist, and finish, affecting strength, elasticity, and appearance. Machine sewing often requires consistent thread tension and correct needle size to prevent fraying or breakage.

In computing, a thread is the smallest unit of execution within a process. Threads within the same process share memory and system resources, enabling concurrent or parallel operations. A program can create multiple threads to perform tasks such as user interface handling, background processing, or I/O while maintaining responsiveness. Threads undergo a lifecycle from creation to runnable, blocked or waiting, and termination. Scheduling and context switching control which thread runs. Synchronization primitives—locks, mutexes, semaphores, monitors—coordinate access to shared data and prevent race conditions. Common pitfalls include deadlocks and livelocks; thread safety and atomic operations are central concerns. Many environments employ thread pools to reuse threads for efficiency and to bound resource usage. There are kernel threads and user-level or managed threads, with varying performance and portability characteristics, and some platforms offer lighter-weight fibers or green threads as alternatives.

Other uses include discussion threads in forums and message boards, or as a term in protocol development for threaded communication. The precise meaning of thread depends on context.