Engineering was the discipline applying engineering sciences, mostly mechanical and electrical, to the development, design, operation and maintenance of spacecraft propulsion and on-board systems.
A starship's engineering department was usually overseen by the Chief Engineering Officer, or Chief Engineer. (HH1)
The engineering department of Royal Manticoran Navy vessels was usually made up of six sections divided into two groups:: propulsion group (impeller, power, and gravitics technicians) and Environmental Group (environmental, hydroponics, and damage control technicians). (TRMN BuTrain-001, Student Manual)