What is Discourse? -English LanguageWatch
It's spoken language, sometimes... but also the structure of texts (spoken or written) beyond the word, phrase and clause level - so, the way in which texts are put together as units, with beginnings, middles and ends/problems and solutions/orientations, complications, resolutions and codas - but also it can be taken to mean threads, arguments, themes in discussions about ideas associated with language. So, you might find discourses of decay in arguments about what texting is doing to language, or discourses of punishment in solutions for dealing with crime, or discourses of correctness when discussing accents and slang.
Frankly, I can't blame anyone who gets confused by this...
To my mind, similarly, 'discourse' is the way in which explicit or implicit social ideas, values, and beliefs, are encoded in the language used by specific groups, political, and institutional units (and many more social units) and individuals within these. Often people will talk of 'discourse' in relation to power-structures, and the way power-structures are encoded in the language used. Churches, for example, have particular discourses which mean that often the language they use is powerfully significant because it relates to tangible social organisation and the mapping of social relations. You have a discourse of salvation, Christian living, church membership, infallibility of the Bible, etc.
The best thing is to make sure you choose a definition which works best for the text in front of you, then apply it.
A simple, fundamental idea to discourse is that in order to understand a line or paragraph or passage you need more than the words or the sum of the words: understanding the words will not give you meaning, beyond denotation or connotation. Understanding the overall sense or meaning of the text is where discourse exists. Discourse is at the intersection of you and the text: you as a sense-making, socialised creature and the text as coded signals.