I am currently reading "The Fragile Absolute" by Slavoj Žižek. In chapter four he talks about the Master-Signifier. I am not very familiar with Lacan's concepts (I think it comes from him), so could someone please explain this concept to me (with an example, please)?
I have read the article linked by Keelan. I am trying to grasp the term. I think the best way would be to try to describe it in my own words. So please correct my brief explanation if/where I am mistaken:
A Master-Signifier is special, because while other signifiers usually point to or signify another thing (which is usually not present, therefore the need for a signifier - something to refer to the object we lack), the Master-Signifier is void of meaning. Other signifiers refer to it, but since it does not point forward, in it the chain of signifiers ends.
From a less careful position, a Master-Signifier is something halfway between the Jungian concept of an archetype and that of an ego-ideal: Father, The Feminine, German-ness, Humane Behavior, etc. as goals to strive for or fixed exemplars that we will not allow to be sullied. The thing signified is not a real or learned connection, but an extrapolation into an idealized image, relative to which all encountered instances are rated according to their failure to encompass the perfect form.
So it is not the word, or the real object, or even the type of the real object, it is more like the Platonic idea of that object, except that it does not emanate from some idealized realm and get cast into the mind, it is derived by the mind from reality through idealization. Given that humans are often quite similar internally, these signifiers are shared, but also personalized -- my ideal of Man is not yours, but we both have one and they will largely overlap.
Well, in lacanian theory all signifiers are intrinsically devoid of meaning; they rely on a signified to provide this. Think back to vocabulary tests in school. Signifiers are like the vocabulary words you had to define, and you had to define them, or give them meaning, with words other than the one you were to define. These other words have, in this context, the status of signifieds.
(As an aside to Jobermark's comment above, in lacanian theory signifiers don't point at 'things.' If they did, this would be very much like what Frege discusses in Über Sinn und Bedeutung. If this was the case, the signifier would be the same sort of entity as a 'proper name', which points at a 'referent'. But, at least in Lacan's views, this is not the case; the signifier only ever points to other signifiers.)
Lacan's theory is intimately tied to Saussure's model of the sign. In his model, the sign has, like a sheet of paper, two sides. One side is the signifier, or "sound image." This is the word shorn from everything other than its phonetic properties (and the ways in which these are represented). On the other side is the signified. This is, in effect, its concatenated concept. (I found a good explanation of Saussure's model here on StackExchange: Saussure and structuralism)
I know you are asking about 'master signifiers,' but I am trying to show that there is no real (i.e. structural) difference between a 'signifier' and a 'master signifier.' The concept of 'master signifier' belongs to ideological analysis, not psychoanalysis proper (which is concerned with the signifier as such). A master signifier could be something like 'freedom' or 'health.' Either way, in its most basic and essential function, the signifier organizes discursive structures. Whether it belongs to a collective or to an individual subject, any and every time you examine a discursive structure, you will find that it is organized by certain signifiers.
Here is an article on metaphor that begins with a good explication of Lacan's use and development of Saussure's concepts of signifier, signified, and sign.
In Lacan's seminars, the first place (that I know of) where the term 'master signifier' is used is Seminar XVII ( English title is 'The Other Side of Psychoanalysis'- the translation, by Russell Grigg and Justin Clemens, is very good). In this seminar Lacan developed his theory of discourse.He begins by drawing on (Alexandre Kojeve's reading of) Hegel's The Phenomenology of Spirit, where Hegel develops the master-slave dialectic. The basic point that Lacan takes from this is that the master depends upon the slave for his very being as master--without the slave's recognition of the master's mastery, the master is nothing. Like this, a signifier, in and of itself, means nothing; this can only be provided by the signified, which 'fills out' the signifier.