Cloud __________ Scaling refers to adding more CPU or memory to an existing server.

Vertical scaling refers to the process of adding more resources, such as CPU or memory, to an existing server to improve its performance. This approach allows a single machine to handle increased workloads without needing to deploy additional servers. By upgrading the server's capabilities, vertical scaling can address performance bottlenecks effectively, especially in applications that require significant processing power or memory.

In contrast, horizontal scaling involves adding more servers to distribute the workload across multiple machines, rather than enhancing a single machine's capacity. Dynamic scaling typically refers to the capability of systems to automatically adjust resources based on current demand, which can include both vertical and horizontal scaling. Elastic scaling is a broader term often associated with the ability to scale resources dynamically based on workload demands, but it doesn't specify whether that scaling would be done vertically or horizontally.

Therefore, the term that specifically describes the act of enhancing the existing server's CPU or memory capacity is vertical scaling.