From Gilles Deleuze lecture course on multiplicity and Bergson. Deleuze opens by saying:

I wanted to propose to you an investigation [recherche] into the history of a word, a still very partial, very localized history. That word is “multiplicity.” There is a very current use of multiplicity: for example, I say: a multiplicity of numbers, a multiplicity of acts, a multiplicity of states of consciousness, a multiplicity of shocks [ébranlements]. Here “multiplicity” is employed as a barely nominalized adjective. And it's true that Bergson often expressed himself thus. But at other times, the word “multiplicity” is employed in the strong sense, as a true substantive, thus, from the second chapter of Time and Free Will onward, the number is a multiplicity, which does not mean the same thing at all as a multiplicity of numbers.

Therefore there are two types of multiplicity: one is called multiplicity of juxtaposition, numerical multiplicity, distinct multiplicity, actual multiplicity, material multiplicity, and for predicates it has, we will see, the following: the one and the multiple at once. The other: multiplicity of penetration, qualitative multiplicity, confused multiplicity, virtual multiplicity, organized multiplicity, and it rejects the predicate of the one as well as that of the same.