A sortal is a concept or term that helps us categorize the world by defining groups, allowing us to identify and count items within those groups. ^3872f6 A sortal: - defines the essence of an item, - distinguishes between items of the same kind for counting, - determines when an item persists or ceases to exist through change. Sortals serve as both **labels** for types of things and as **predicates** for differentiating, counting, and tracking their existence. ^678a53 Sortals function as both names and predicates for uniqueness and sameness. ^364dc5