As promised, here is Alasdair MacIntyre's definition of "practice."

By a practice I am going to mean any coherent and complex form of socially established cooperative human activity through which goods internal to that form of activity are realized in the course of trying to achieve those standards of excellence which are appropriate to, and partially definitive of, that form of activity, with the result that human powers to achieve excellence, and human conceptions of the ends and goods involved, are systematically extended.

From Alasdair MacIntyre, After Virtue, 2nd ed. Notre Dame University Press, 1997, p. 187.