What does pfSense stand for/mean?

The project ran for months with no name. In fact, the FreeBSD jail that ran the CVS server was called projectx until the project was migrated to git several years ago.

Locating an available domain name was the primary difficulty. The project founders, Scott and Chris, ran through numerous possibilities, eventually settling on pfSense® because the firewall would make sense of the packet filtering software used, pf.