You have started a new "thread" with this query - the answers to it form the whole thread. It is a category of no. 4 below
noun 1 a long, thin strand of cotton, nylon, or other fibres used in sewing or weaving.
2 a long thin line or piece of something.
3 (also screw thread) a spiral ridge on the outside of a screw, bolt, etc. or on the inside of a cylindrical hole, to allow two parts to be screwed together.
4 a theme or characteristic running throughout a situation or piece of writing
• verb 1 pass a thread through.
2 move or weave in and out of obstacles.
3 threaded (of a hole, screw, etc) having a screw thread