It depends. In America at least people generally mean Herbal tea to mean any beverage steeped with plants that is not made with the actual tea plant. They also may or may not be including Yerba Mate in this, which is a South American beverage made with a different plant, but still caffeinated. In other cooking context Herbs pretty much mean fresh (not dried) plants that are used to add an aromatic flavor, such as Basil or Rosemary. A chef would not refer to a carrot as an herb.