These are often vague and undefined. Here are some good sci fi ones:
Construction: The theory and practice of civil engineering. The construction engineer can envisage a construction project (a habitat, bunker, airstrip or road, for example), draw up plans and costings and then oversee the actual construction by a crew or robots.
Biotechnology:The relatively new technology of biologicals includes DNA work, retro viruses and other bio-modification. It is in its very early days and on a small scale, far from the lofty goals of transhumanism! This industry is mainly used to modify crops for survival in hydroponics units on large scale colonies, or on the Martian surface.
Hydroponics: Construction and maintenance of enclosed self-sufficient greenhouses that have become crucial to life on many worlds, and as a life support system on deep space vehicles.
Materials Technology : Knowledge of the chemical makeup of industrial materials including glass, acid, steel, polymer and a hundred other materials. The character is able to create a desired substance provided he has suitable equipment (typically a workshop or auto-factory) on hand. This specialism incorporates industrial chemistry as well as metallurgy