The term "graphene" has been attributed to a lot of things at this point. Initially, it meant only monolayer graphene, but people expanded it coining the term "multilayer graphene" (or thin graphite, as I prefer to call it) which they expand up to 30 layers although graphene loses many of its fancy properties as soon as 3-5 layers are stacked.

So, when you buy "graphene", you have to be careful as hell what you are buying, because it may be anything from actual monolayer graphene to 30 stacked layers.