In college speech cantilever becomes, “Can’t I leave her?”
Though most certainly this interpretation has no bearing whatsoever on this type of “flying-lever bridge,” no satisfactory source of the canti- element has been determined.
As a term in architecture, the name appeared in the seventeenth century, pertaining to a masonry bracket of much greater length than depth.
Two such brackets united at the tips became a cantilever bridge early in the nineteenth century.