Another good but flawed definition from the British Institution of Structural Engineers, is…
Structural engineering is the science and art of designing and making, with economy and elegance, buildings, bridges, frameworks and other similar structures so that they can safely resist the forces to which they may be subjected.
This sounds pretty good, right? Unfortunately, it fails completely in describing how one goes about designing. Like all other definitions, it puts too great an emphasis on force resistance. Yes, we proportion members based largely on forces, but that is only one of many design considerations – we also have to take construction practices, architectural constraints, client needs, and many other factors into account. As Hardy Cross put it, "Strength is essential, but otherwise unimportant."