What is the difference between a DoS and a DDoS?

A Denial of Service (DoS) attack involves a single source overwhelming a target system with traffic or requests, rendering it unavailable to legitimate users. In contrast, a Distributed Denial of Service (DDoS) attack uses multiple compromised devices (often part of a botnet) to launch a coordinated attack, making it more difficult to mitigate due to the sheer volume of incoming traffic from various sources. Essentially, the primary difference lies in the number of attacking sources involved.