This is a subentry of a reading guide to HTT.
(morphisms in enriched categories)
In a model category there are stricly speaking no morphism defined but only hom objects. So if we wish to define the notion of an enriched model category where we expect to have distinguished classes of morphisms we need to refer to an associated (ordinary - i.e. -enriched) model category where we have morphisms and to qualify our morphisms there as cofibrations, fibrations and weak equivalences, respectively. This is explicated in the following way:
Let be a monoidal category. Let denote the set of objects of . Let denote the terminal -category ; i.e. has precisely one object and the monoidal unit is defined to be the hom object . Let denote the terminal category. Let . Let denote the 2-category of -categories. Then there is a functor
called the underlying set functor.
So if we speak of a cofibration, fibration or weak equivalences in an enriched category we mean in fact .
Ross Street, basic concepts of enriched category theory, pdf