Target/Bull BBL

I heard or read the other day that a target barrel and a bull barrel are two different styles of barrel. Is this true? I’ve always thought they were one in the same, so if it is true what makes one different from the other? Whats the progression of sizes when it comes to AR barrels? Thanks-

AFAIK:

Pencil
Gov’t Profile
Medium
H-Bar
Bull.

If I’m wrong someone will be along shortly to correct my mistake.