Full Idea
'Difference' is a term which Deleuze uses to refer to that which eludes capture.
Gist of Idea
'Difference' refers to that which eludes capture
Source
report of Gilles Deleuze (Difference and Repetition [1968]) by Todd May - Gilles Deleuze 3.03
Book Reference
May,Todd: 'Gilles Deleuze' [CUP 2006], p.82
A Reaction
Presumably its ancestor is Kant's noumenon. This is one of his concepts used to 'palpate' our ossified conceptual scheme.