Board Thread:False Info and Speculative Discussion/@comment-25178327-20140416192224/@comment-13965604-20140417223227

86.4.82.94 wrote: Derek is not  an Omega. An Omega is the weakest of all werewolves  often kicked out of the pack or bullied by other pack members into leaving. Omegas are not 'lone wolves' in fact they need a pack to help them survive  but because of the above are often alone or between packs. IRL they are often the youngest pack members  and their status changes with age. If you remember right after the insult Derek said, "I may not be an Alpha but  can still fight like one." That's not an Omega. 'Lone wolf' is just that and can be Alpha, Beta or Omega. Alphas looking to build a pack, Beta's seeking mates and building a family pack thereby becoming and Alpha or an Omega. Derek is best described as an apex Beta, just below an Alpha and chooses to live without a pack.

Except that's not what has been told to us on the show. We've been told two things. One is that omegas, in the shows canon, are lone wolves who are weaker because they don't have the support of a pack. The other is, as the twins stated and you said, the weakest member of the pack who is bullied and shit. Derek still could fall into the first category.