Actually, these two terms are used interchangeably through this site and with most manufacturers and retailers. The fact is that both pizza and baking stones are made from the same materials, come in the same shapes and are used and cleaned the same way.
Remember the use of a pizza stone or baking stone is all just an easier and more convenient method of cooking than using a traditional stone oven. Historically people have been baking pizzas and breads, and everything else for that matter, in clay or stone ovens since the 19th century. These ovens were found throughout the world, which
demonstrates their efficiency and effectiveness. While there are many reasons that stone ovens have been used for thousands of years, one of the primary reasons is the way the heat is transferred evenly throughout the food. This increases the likelihood of your bread or pizza crust being fully and evenly cooked. Every beginning bread maker has experienced a loaf of bread that didn’t fully cook inside, even though the crust is perfect. Many modern restaurants have built stone ovens into their restaurants and marketing campaigns. While most people don’t have the room or finances to build a stone oven in their home, a pizza stone or baking stone is an easy and economical way to bring the same benefits to your kitchen today.
The only real consideration that might result in a difference is the shape. If you are just making loaves of bread, then an appropriately sized baking stone might be your best choice. If instead, you plan on only making traditionally round pizzas, then a round stone may be best. Of course there are no rules that say you can’t make round loaves of bread or square pizzas!
Bottom line is if you find just the right size and priced stone that is labeled as a pizza stone, and you want to make bread, buy it.