“Convention generalizes precedent to situations where one lacks shared experience, but knows that everybody involved is a member of the same community. An observable regularity in the behaviour of members of a community in a recurrant situation is a convention if it is customary, expected, and mutually consistent, compare (Lewis (1969) and Young (1993).”

from 1997, John B. Van Huyck, Raymond C. Battalio, and Frederick W. Rankin, ON THE ORIGIN OF CONVENTION: EVIDENCE FROM COORDINATION GAMES, The Economic Journal 107 (May), 576-696, Blackwell Publishers.
Lewis, David. 1969. Convention: a Philosophical Study. Cambridge, MA: Harvard University Press.