In cloud computing, "scalability" refers to the ability of a system to adjust its resources to accommodate varying workloads. It enables organizations to increase or decrease their computing resources—such as storage, processing power, or bandwidth—dynamically based on demand. There are two main types of scalability: vertical scaling, which involves adding more power to existing resources, and horizontal scaling, which involves adding more machines or instances to handle increased load. Effective scalability is essential for supporting growth and ensuring that applications maintain optimal performance during peak periods and quiet times alike.