Engineering
Engineering is the creative application of science, mathematical methods, and empirical evidence to the innovation, design, construction, operation and maintenance of structures, machines, materials, devices, systems, processes, and organizations. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering.
Professional
A professional is a member of a profession or any person who earns their living from a specified professional activity. The term also describes the standards of education and training that prepare members of the profession with the particular knowledge and skills necessary to perform their specific role within that profession. In addition, most professionals are subject to strict codes of conduct, enshrining rigorous ethical and moral obligations. Professional standards of practice and ethics for a particular field are typically agreed upon and maintained through widely recognized professional associations, such as the IEEE. Some definitions of "professional" limit this term to those professions that serve some important aspect of public interest and the general good of society.
Engineering
Engineering is the art of directing the great sources of power in nature for the use and convenience of man.
Thomas Tredgold (1828), used in the Royal Charter of the Institution of Civil Engineers (ICE) published in: The Times, London, article CS102127326, 30 June 1828.
Professional
Towards this fine honor of a trade converged all the finest, all the most noble sentiments—dignity, pride. Never ask anything of anyone, they used to say. … In those days a workman did not know what it was to solicit. It is the bourgeoisie who, turning the workmen into bourgeois, have taught them to solicit.
Charles Péguy, Basic Verities, A. & J. Green, trans. (New York: 1943), p. 83