By Top is usually denoted the collection of topological spaces and continuous maps between them.
How exactly this is understood depends a bit on context: of course forms an ordinary category. But it is also naturally an (∞,1)-category. This, in turn, may be presented by regarding as a model category equipped with the Quillen model structure.
Moreover, what exactly counts as an object in often varies in different contexts. For many applications it is useful to restrict to a subcategory of nice topological spaces such as compactly generated spaces or CW-complexes.
The homotopy category of Top with respect to weak homotopy equivalences is Ho(Top). This is the central object of study in homotopy theory. Regarded as an (∞,1)-category is the archetypical homotopy theory, equivalent to ∞Grpd.