Both words have been in use for several centuries to denote the plural of
person, the difference usually being explained in terms of
people referring to a group of which the exact number cannot be determined or is irrelevant and
persons to a number of individuals who are countable or regarded separately:
A great many people feel that a hug can make their day—Chicago Tribune, 1991
It is morally certain that a number of persons signed confessions to crimes of which they were innocent—K. Lindsay, 1980.
However, this distinction is not watertight, as the following examples show:
Persons may squat in buildings by reason of inability to find other accommodation—Oxford Companion to Law, 1980
It now numbers some 40 people, as well as the Jersey cows, the Aberdeen Angus bull, the horse, three ponies, and a handful of fecund goats and breeding sows—Country Living, 1991.
To judge from the recent evidence, the distinction is based as much on context as on meaning, with
people used as the general word and
persons used in more formal contexts (e.g. law) and to emphasize individuality. The plural
Persons (and generally not
People) also occurs in compound forms such as
barpersons,
chairpersons,
spokespersons, and other gender-neutral forms. An exception is
sportspeople, which is typically treated collectively in usage.