unit of thought that corresponds to properties that are common to a set of objects
characteristic which is indispensable to understanding a concept
[ISO 1087-1:2000, definition 3.2.6]
essential characteristic used for distinguishing a concept from related concepts
NOTE The delimiting characteristic support for the back may be used for distinguishing the concepts stool and chair.
[ISO 1087-1:2000, definition 3.2.7]
characteristic that is always true of each object in the extension of a given concept
characteristic that is one of a set of characteristics that determines whether a specific object belongs in the extension of a given concept
NOTE A sufficient characteristic is not necessarily true of all objects in the extension of the concept.
EXAMPLE Any object that has the properties corresponding to the characteristics ‘having given birth’ and ‘being human’ belong in the extension of the concept ‘woman’, but not all women have given birth.