A feature which, when possessed by the dingus, at least partially qualifies said dingus as being of some particular class (often, but not always, a design). That is, such a feature is considered essential to the “character” of the dingus.
In the common usage, a characteristic can be represented in an unstructured manner as text or picture. Contrast with “Technical Characteristic“.
Characteristics are often used prescriptively, when construed as requirements. They can also be used descriptively when employed as the basis for Selected Item Drawings, Vendor Item Control Drawings, Altered Item Drawings, and so forth. In the later case, the drawing types mentioned can re-construe mere “features” of an existing design as being characteristic of a newly defined Part Number or Administrative Control Number. This practice has been known to seriously bake the noodle of many System Engineers, who are often unfamiliar with those concepts.