Scalability

Scalability is how well a system or a business can handle a lot more work without slowing down or falling over, ideally by adding resources rather than being rebuilt. A scalable online shop copes with ten times the visitors on sale day by drawing on more computing power, not by crashing.

It is like a restaurant designed so it can add tables and staff for a big night, rather than one where a full room means turning people away. Scalability matters because success brings load, and a business that cannot grow smoothly can be undone by its own busiest, best days.