cantilever
n. countablen. a beam or structure that is supported only at one end. It sticks out over a space without any support in the middle, like a diving board.
n. a rigid structural member fixed at one end and projecting into space, supported only at the fixed end. Often used in architecture and engineering to create overhangs or spans without intermediate supports.
The bridge uses a cantilever to span the deep valley.
The architect designed the balcony as a cantilever, allowing the floor to extend over the garden without any visible pillars.
Modern skyscrapers often employ a cantilever system to distribute the immense weight of upper floors across a smaller footprint, creating more open space at the building's base.
First attested in the 1660s, probably from cant (“slope, edge, corner”) + lever, but the earliest form (c. 1610) was cantlapper. First element may also be Spanish can (“dog”), an architect's term for an end of timber jutting out of a wall, on which beams rested.