Packages / Ports Collection
Hierarchical list of recipies to build various bits of software
Contains useful software which isn't within OpenBSD itself
Not part of OpenBSD itself
E.g. -- to install the port of vim
cd /usr/ports/editors/vim make make install
Details of any patches to the source are stored and the source patched
Installation is registered as installed -- the same as for a package
Packages are simply compiled ports.