Term used by Locke (Essay, iii. 3) and resurrected by Strawson (Individuals, p. 168) for a noun or ‘predicable’ such as ‘man’, ‘woman’, ‘tiger’, that provides a principle for individuating and counting examples of things of a type. ‘Butter’ and ‘thing’ are not sortals because there is no principle for counting butter (as opposed to pats of butter, etc.) or things (you cannot tell when you have one thing or two). ‘Red’ is not a sortal but an adjective. See also count-noun.