Does inter-ethnic refer to things that are between different ethnic groups, or within one ethnic group?
If it refers to things that are between different ethnic groups, what word would be used to refer to things that are within one ethnic group?
Inter means between. The Latin prefix for within is intra. However I wouldn’t use “intra-ethnic” — in fact I can’t think of a sentence which would refer to “things within one ethnic group”. One might talk perhaps of “inter-ethnic conflict”, but “intra-ethnic conflict”? I think not: it would be “ethnic Europeans (for example) are fighting amongst themselves”.