Screws

"Screw" on Wikipedia:
https://en.wikipedia.org/wiki/Screw

"Screw Thread" on Wikipedia:
https://en.wikipedia.org/wiki/Screw_thread

Wood Screw Chart:
http://www.wlfuller.com/html/wood_screw_chart.html

Understanding Screw Sizes:
http://diy.stackexchange.com/questions/13824/understanding-screw-sizes

Screws Explained:
http://handycrowd.com/screws-explained-gauge-size-pilot-holes-and-wall-plugs/