The term "high definition" is overused.  It makes sense for HDTVs because they're literally higher quality and resolution than their standard counterparts.  But for things like HD radio and HD camera lens filters (one of which I just bought recently), it's a misnomer.  HD radio is simply digital radio, and the HD camera lens filter is simply better than its previous version.  The inclusion of HD is both products' names is simply a sales tactic.  (Naysayers may point out that the sales tactic worked in the case of the camera lens filter, but I will say, "Wrong!  That was the only one in the store.") #technology