Discourse

The term 'discourse' is used in several different seneses within the same and seperate academic disciplines (Weiss and Wodak 2003: 13).  Michael Foucault, an important thinker who has been a major influence in CDA, defines 'discourse' as ‘the general domain of all statements, sometimes as [1] an individualizable group of statements, and sometimes as [2] a regulated practice that accounts for a number of statements' (1972: 80).

Inspired by Foucault's first sense of 'discourse', Norman Fairclough applies the concept of 'order of discourse', where the order of discourse is the totality of texts about a particular topic (1995: 132).  Inspired by Foucault's second sense of discourse, Kress (1985: 6) states that discourses provide 'a set of possible statements about a given area, and organises and gives structure to the manner in which a particular topic ... is to be talked about'.  Teun Van Dijk (1985, 1988, 2008, 2009, 2010) adopts a cognitive perspective and sees the production and interpretation of texts as constrained by 'situation' or 'context' models in social cognition. 

In contrast to these Foucauldian notions, 'discourse' as used in linguistics refers to language-use, which is to say the practice of producing and interpreting text.

Henry Widdowson (1995: 169) has suggested that 'discourse' has been used so widely across the social sciences that it no longer has any definable meaning.