Différance is a pun in French, which arises out of two meanings of the French word différer.  The first meaning of the word involves deferral—in the sense of postponement—and the second meaning concerns difference.  In the works of Jacques Derrida, différance refers to the idea that words and signs can never truly summon forth what they mean, but can only be defined or explained through the use of more words.  Instead, the meaning of a word is always the “absent signified,” which Derrida calls the trace.  Therefore, words and signs are always different from what they mean, and the actual entities to which they refer are always postponed by human language. Using the concept of différance, Derrida argues that because the perceiver’s mental state is constantly in a state of flux and differs from one re-reading to the next, a general theory describing the role of memory and perception in the understanding of sequential data is unachievable.  As a result, individuals find themselves enclosed in an inescapable web of language, which shifts each time one hears or reads a given utterance.  There is a deferment of meaning with each act of re-reading, as well as a difference of readings with each re-reading.  Différance usually describes the moment of re-experience, the re-arrival of the moment of reading.