The long strange trip
Technology level or Tech Level is a measure of technological capacity. Usually this is used in a UWP (Universal world profile) to indicate the overall technology of the planet. (A planet may have large sections, and/or populations at a more primitive level than listed).
Technology does not imply standard of living as workers in a high tech industrial world can have a poorer quality of life (perhaps not having the money to pay for high-tech health care), than a medieval farmer. The tech level does impact the exchange rate for the planet, and has a large effect on its economy and interstellar trade.
Enhanced tech levels describe the technology for different classes of technology (e.g. a planet may have a medical tech level different from its weapons tech level).
Tech levels are measured in the range 0-15 (0-F), with 0 representing extreme primitive levels (hunter/gatherers), and 15 the height of Imperial technology, however there is technology beyond that of the imperium as evidenced by ancient sites. (e.g. Rosette worlds are TL21 and Rigid Dyson Spheres TL27).