The term intracultural is used to describe data and interactional data from within one cultural group. For example: Value variations among Palestinians are intracultural. Often used in Subaltern Studies, Development Studies and Sociology.
In terms of Cultural Theory, and as a simple way of looking at the terms, Interculturalism and Intraculturalism are not the same thing. For example, when looking at a situation of social gathering, 'Interculturalism' would imply the mixing of the various cultural components to form a new, different whole, very much in the same way that Hegel's theory of Dialectics involves a Thesis and Antithesis interacting to form a new, different Thesis. This theory could be used to argue that cultural identity is always in a state of flux, and that it is not truly possible to define as a result.
Intraculturalism involves that same group coming together to form a whole, with the different groups still retaining their various 'original' defined identities. The various components are still 'suspended' intact within the whole and are unchanged by the merge. For instance, you may imagine large populations or annexes of people living together in a particular area of a town, having migrated there from abroad and retained their own sense of community, ritual and custom while living together.
The difference between the two 'isms' is the site of heated contemporary debate, particularly between conflicting 'Eastern' and 'Western' schools of thought, and whether they can truly be housed together comfortably and harmoniously without loss of identity on either side.