"What is a "Tek" screw?
A Tek screw is a screw which drills its own hole, then threads it. A Tek Screw will drill, tap, and fasten in one operation. It is used for assembly of wood to metal and metal to metal.
Use either air or electric drivers equipped with standard clutches which disengage the torque output when the screw is properly seated. It is not necessary to dimple material.
To measure length - measure from under the head to the end of the thread. "
http://www.homeproassortments.com/faq.htm

"Self-Drilling Tapping Screw (Tek Screw) "
http://www.hssales.com/product_specifications.htm

maintenant je suppose que ce doit être un acronyme, ou que c'est effectivement le nom de la première marque qui en a fabriqué (phénomène "Frigidaire" ou "Kleenex")