ETYM Old Eng. threed, thred, as. thraed; akin to Dutch draad, German draht wire, thread, Old High Germ. drât, Icel. thrâthr a thread, Swed. trad, Dan. traad, and as. thrâwan to twist. Related to Throw, Third.
A fine cord of twisted fibers (of cotton or silk or wool or nylon etc.) used in sewing and weaving; SYN. yarn.

To pass a thread through

1. In programming, a process that is part of a larger process or program.
2. In a tree data structure, a pointer that identifies the parent node and is used to facilitate traversal of the tree.
3. In electronic mail and Internet newsgroups, a series of messages and replies related to a specific topic.
Each process has one or more threads assigned to it. Threads are the part of the program that execute.