Bread Flour
Bread flour is all-purpose flour with a bit more protein (around 14% vs around 9% in all-purpose flour). The extra protein can come from additives or from the type of wheat used.
You can make bread with all-purpose flour, but bread flour will rise more.
Adding "Vital Wheat Gluten" to all-purpose flour will give it extra protein and better rise, but this isn't something most people would have on hand.