The term ism in medieval Arabic grammatical tradition: A hyponym of itself

The term ism in the Arabic grammatical tradition is a hyponym of itself. In other words, it can refer to the entire class of words belonging to the part of speech ism, or to just a subclass of this part of speech. In the latter sense it always stands in opposition to one of three other subclasses of this part of speech, viz. scombining dot belowifa, mascombining dot belowdar and zcombining dot belowarf; the subclass defined by the former is more focal than the one referred to by each of the latter. This interpretation resolves a difficulty stemming from cases where ism and one of the three other terms refer to two mutually exclusive classes, although the latter always refers, in the contexts in question, to a subclass of the part of speech ism.