Not entirely certain what is being asked here, but if you mean what is the name of Ichigo's inner Hollow, then he has claimed that he does not have a name. If you mean what is the name of Ichigo's full Hollow form, then no name for it has been revealed. There is not one, but people tend to call him Hichigo, Hollow Ichigo, Shirosaki, Ogihci. Alternatively, he once called himself Zangetsu, referring to the fact that as a part of Zangetsu, the inner Hollow represents a piece of Ichigo's power.