A measure of how advanced your technology is. The higher your tech level, the better the ships and weapons you can build. Each starbase has four tech levels for the areas starship hulls, engines, beam weapons and torpedoes. You can buy additional tech levels by spending money. Raising the tech level on one starbase gets you the additional components only there.
Unregistered players can only buy up to Tech 6, registered ones can buy all levels up to Tech 10. Some natives give you Tech 10 for free, even when you're unregistered.