crossbar

A crossbar is a horizontal structural member that connects two supports, distributing loads and providing stiffness. The term is used in several domains, including engineering, architecture, sports, and transportation.

In telecommunications and computer engineering, a crossbar switch or crossbar network uses a grid of crossing conductors with switches at each intersection. Any input can be selectively connected to any output, enabling flexible routing with low switching latency. Crossbar switches were central to early electromechanical telephone exchanges and remain a reference in certain dense memory and reconfigurable systems. Modern networks typically rely on more scalable fabrics, but crossbar concepts influence dense crosspoint arrays in resistive and phase-change memory.

In construction and mechanical design, a crossbar is a transverse bar that links uprights or frames. It adds horizontal stiffness to trusses, gates, fences, scaffolding, and vehicle frames, and can serve as a mounting surface for accessories or components.

In sports and games, the crossbar refers to the horizontal bar forming the top of a goal. Attempts must clear the crossbar to count, and the crossbar also serves as a reference point in various scoring and offside rules.

In bicycle and vehicle design, crossbars are horizontal tubes that connect main structural elements, contributing to rigidity and alignment and supporting components such as handlebars, racks, or seats, depending on the design. Crossbars thus play both functional and structural roles across a range of applications.