What does pfSense stand for/mean?

The early tag line for the pfSense open source project was “making sense of pf”, referring to the packet filter technology at the core of the project.

PF in FreeBSD can perform many of the basic packet filtering and QoS firewall tasks that pfSense software provides, however, pfSense software makes it easier to manage, monitor, and maintain. It accomplishes this by layering an easy to use GUI and customized services on top of the operating system and relevant packages, resulting in a complete firewall/router/VPN solution that is capable of much more than the sum of the underlying components.