Persons who possess educational qualifications, work experience, and legal certification where required as established by engineering schools, employers, and licensing authorities for employment in various fields of engineering. Engineers typically function in one or more activities, such as research, development, design, production, consulting, administration and management, teaching, technical writing, or technical sales and service.

Classifications are made according to one or more engineering fields in which individual is qualified for employment, such as aeronautical, electrical, mechanical, chemical, mining, marine, or nuclear engineering.