Editing Screw thread (section)

===Gender===
{{Main|Gender of connectors and fasteners}}
Every matched pair of threads, ''external'' and ''internal'', can be described as ''male'' and ''female''. Generally speaking, the threads on an external surface are considered male, while the ones on an internal surface are considered female. For example, a [[screw]] has male threads, while its matching hole (whether in nut or substrate) has female threads.  This property is called ''gender''.  Assembling a male-threaded fastener to a female-threaded one is called ''mating''.