A technician was a person (often a crewman) trained in a specific process, often of a technical nature.

In 2364, sensor technicians were dispatched to work on a "glitch" with the USS Enterprise-D's sensor readings that were indicating there was something in orbit, despite the fact nothing appeared on the viewscreen. (TNG: "Justice")

In 2367, Vagh requested that his own technicians be allowed to confirm Captain Picard's claim that a Federation phaser rifle had been charged using Romulan technology. (TNG: "The Mind's Eye")

In 2370, Deela, an official at the Tozhat Resettlement Center, complained that the center's computers didn't work, and a technician hadn't arrived since they were not a top priority. (DS9: "Cardassians")