I recently realized I am a little confused (no comebacks on this admission,please)about altus and old dough. I have seen recipes that refer to using "old dough"(unbaked bread dough?) as part of a recipe and then there is "altus" or "old bread" (usually rye).

Am I understanding it correctly that altus and old bread are the same thing? Both are baked bread that is old/stale? How is it used-ground to crumbs? Soaked and shredded?

Then is "old dough" a lump of unbaked bread dough? How is this kept until it is used? This technique must be best used if there is a bake every day or every other day, like maintaining a starter-best used often so there is no wastage. I am assuming this.