Aptitudes come in three classes.
Common: these are the base level or most general Aptitudes. They are sufficient for most basic activities and advance. In both the number of aspects and the understanding of them.
Example: blacksmithing
Superior: these are more generalized aptitudes that focus on one branch of the study or one craft type. These act as common for basic tasks Of that branch, but are one step less difficult on the victory chart for general tasks that this fits into.
Example: weaponsmithing
Rarified: this aptitude is very specific. Often something that takes years to improve, these aptitudes are a set form of a branch of a task. These are one or two steps less difficult for a superior or common aptitude Task that these fit into.
Example: Damascus steel patterns.
Appellative: a common, superior or rarified aptitude that is so varied that it must be named and may be improved in levels for each name. This is most often used for languages, branches types of animal training and craft aptitudes.
Example: fox hunting dog training.
