Capable of being increased in size, or more accurately, capable of delivering an increase in performance proportional to an increase in size. A scalable architecture is one that can be used as a design for arbitrarily large machines, or one whose increase in performance is linear in the amount of hardware invested. The term is also applied to programming systems, although its meaning is less clear in these cases. It is generally used to imply that the methods and algorithms employed in such systems are in principle capable of performing correctly equally well on large and small hardware systems.