What's the difference between "Release" versus "Errata" versus "Security" branches???

[edflecko .]

Can someone explain what the differences between these three are for me?
These sure sound a lot alike to me -

http://www.bsdnow.tv/tutorials/stable-current - "The -RELEASE branch is
arguably the most stable branch of FreeBSD. That's exactly what it's
designed to be, what the everyday end user installs and uses. When a
-RELEASE is cut, the only updates it gets are either critical fixes or
security flaws."

http://harrykar.blogspot.com/2010/07/freebsd-upgrading-it.html - Errata
Branches  An errata branch is a particular FreeBSD release plus any
security and stability patches issued for that release.

http://www.freebsdwiki.net/index.php/FreeBSD_Release_Branches - "If
stability is the most important factor on this system, you may want to
track something called the security branch. This branch only updates for
security updates and major bug fixes from the code you originally
installed."

Thank you!

Ed