Fig 2.

A Protégé “slot.” This screen capture shows a frame in Protégé representing the slot called “Name,” which is used to convey the unique identifier name for a RadLex term. This name slot contains facets–components that constrain its values such as cardinality, value type, minimum, and maximum values. In this case, the facet values are saying that Name is a single-valued string, and it must have a value for every term in RadLex. This slot is associated with all classes in RadLex; for example, for the supraaortic valve area class (Fig. 1), this slot has a value of “RID482.” Another slot called Preferred Name is used to store the actual name of the class, “supraaortic valve area” (Fig. 1).