[common; from mathematical usage] Combining simplicity, power, and a certain ineffable grace of design. Higher praise than ‘clever’, ‘winning’, or even cuspy.
The French aviator, adventurer, and author Antoine de
Saint-Exupéry, probably best known for his classic children's book
The Little Prince, was also an aircraft designer.
He gave us perhaps the best definition of engineering elegance when he said
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take
away.