It’s a language-specific distinction, mostly referring to the temperature and secondarily to what you’re cooking (dough vs. others). Other languages deal with it differently. For example:

• Italian merges “bake” and “cook” into “cuocere” (ho cotto il pane = I’ve baked the bread), but keeps “roast” distinct as “arrostire” (ho arrostito la carne = I roasted the meat).
• Portuguese doesn’t bother with the distinction. Roast, bake, both are “assar” (assei o pão = I’ve baked the bread; assei a carne = I’ve roasted the meat).

You could also say something like “ho arrostito il pane” (lit. “I roasted the bread”) in Italian but the meaning is different - you’re toasting the bread, not baking it.

In general you’ll use a higher temperature when roasting than when baking, but there are a few exceptions - like, pizze are baked, but a pizza baked on low temperature is a sad pizza. For stuff like beef ribs (that are cooked on low temperature) I’ve seen people using both “baking” and “roasting”.