The FreeBSD Ports Collection is a collection of software with a standard means of compilation and installation. FreeBSD is a source distribution (whereas Debian is a Binary Distribution). Packages come in source-code form with a Makefile suitable for installing the program on a FreeBSD system. The ports collection is very large (around 9000 packages).
Some things may be simpler with a source distribution than with a binary distribution. For instance, since the code is expected to be already on the machine and buildable, when a new compiler is installed one merely needs to rebuild the dependant libraries. In contrast, with a binary distribution like Debian one must wait for a new binary package to be made available. However, as I understand it, FreeBSD has no means of recompiling dependant packages automatically when a new compiler is installed.