Gbps means gigabits per second, a unit for measuring data transfer capacity or throughput. It describes how much information a link, device, or network path can move each second, not how fast a single file necessarily downloads in practice.
In cyber security, Gbps matters because many attacks are limited by bandwidth. Large distributed denial-of-service floods, mass scanning, and bulk data exfiltration can be measured in gigabits per second, and defenders must size firewalls, load balancers, and mitigation services to handle that volume. It is also a common way to compare the capacity of internet links, VPNs, and security appliances. A system rated for 1 Gbps may still struggle if overhead, packet loss, or concurrent sessions reduce real-world throughput, so Gbps should be read alongside latency, packet rate, and utilization.