<p>I looked it up in Wikipedia, and there is only one line there. Anyone have a more detailed description for it? Ubuntu releases their OS with this notation, but I was unable to find a detailed description over what it means/includes. I've already read the Ubuntu notation but need a more general description, not how Ubuntu has implemented it.</p>

From the Ubuntu Wiki:
LTS is an abbreviation for “Long Term
  Support”.
We issue a new desktop and server
  release every six months. That means
  you'll always have the latest and
  greatest applications that the open
  source world has to offer.
Ubuntu is designed with security in
  mind. You get free security updates
  for at least 18 months on the desktop
  and server.
With the Long Term Support (LTS)
  version you get three years support on
  the desktop, and five years on the
  server. There is no extra fee for the
  LTS version, we make our very best
  work available to everyone on the same
  free terms. Upgrades to new versions
  of Ubuntu are and always will be free
  of charge.